Botox Party: Are They Safe?

While Botox is a safe procedure in the right hands, it is not something that can be done by anyone, anywhere. It amazes me that people turn their faces over to any "beauty professional" to administer a medical injection that chemically denervates your facial muscles. Yes, the effect is temporary, but there are real complications that can occur. This should be performed by an appropriately trained physician (board certified plastic surgeon, dermatologist, oculoplastic surgeon, or ENT surgeon) or someone directly trained by and supervised by a physician.
When you go to a Botox party in a non-medical setting, it is really hard to ensure safe practices and appropriate medical record keeping. What are the training/credentials of the injector? Do they even know what muscles they are injecting, or how to fix any problems they cause? Do you have a way to contact him or her after the party? Do you have any follow-up? Is the product being used really Botox? Is the lot number, expiration date, and amount of product used recorded in any medical chart? Were you informed of all of the potential risks, asked if you were pregant, informed of the expected results and what to do if you are not satisfied? Are you getting one-on-one attention with your injector, or are you literally in the middle of a party setting? Did you sign an informed consent? Is there alcohol involved? Were you under pressure by friends or the injector? Is there appropriate equipment to provide sterile technique? Did he or she take the time to analyze your face specifically? Was a medical history taken?
The real answer to your question depends on what you mean by Botox party. The above refers to social gatherings in a non-medical setting, with an injector offering Botox to the attendees. Often the person injecting is not properly trained or qualified to perform the injections, may or may not be a licensed practioner, or may not even understand how Botox works.
I strongly urge you to seek out a professional who is trained to provide this medical service, rather than getting injected at some random party or the corner salon offering cheap prices. There is a reason the prices are cheap. You don't want to learn the hard way that yes, it does matter who injects your Botox.
Good luck!

All three of the neuromodulators that are commonly used and FDA approved for cosmetic use in the US (Botox, Dysport, Xeomin) are extremely safe, when in the right hands. 
Any horror stories that you hear are likely performed by unlicensed providers at a medi spa, home injection party, dentists office, etc. 
When put in improper places with incorrect doses, problems can definitely happen.
These unqualified injectors, although especially prevalent where I practice, are everywhere across the US. Choose somebody whose entire practice revolves around facial anatomy, facial cosmetics, and who's training was specific to that - this is not your cardiologist or geriatrician who took a few weekend courses. Stay away from the dentist, internal medicine doctor, family practice doctor, etc who decided to inject Botox on the side to make a few extra bucks. You often find the best deals with these unqualified providers or medi spa's, but you will get what you pay for in the end.  It is also worth noting that just because somewhere does a lot of Botox does not necessarily mean they are good at it; doing the same thing wrong a thousand times just makes one better at doing it wrong.
Scientifically: 
Botulinum toxin was first isolated in the 20s, was first used therapeutically in 1968, and became approved in 1989 for eye issues. It has been used heavily for cosmetic use since 2002, and it was the first aesthetic drug ever approved.  All that is to say...it has a lot of safety data behind it. Recent evidence (coming out this week) proves that botulinum toxin does NOT enter your brain as it's distant cousin tetanus toxin does, which is where that theory came from. 
Botox, Dysport and Xeomin are the 3 botulinum toxins approved for cosmetic use in the US. They all work in the same way, at the presynaptic terminal blocking the release of acetylcholine - making the nerve temporarily unable to communicate with the muscle. It is broken down as a protein in our body with liver metabolism. Effects are temporary, and repeated use serves to take tension off of your skin, relaxing lines and wrinkles.
To ensure you are receiving the highest level of care, seek out a modernly trained, new-school dermatologic surgeon, oculoplastic surgeon, facial plastic surgeon or plastic surgeon who is board certified and fellowship trained in one of these "core four" cosmetic specialties. Membership in organizations like the American Academy of Facial Plastic and Reconstructive Surgery help to identify a highly trained surgeon.
Cameron Chesnut
#realself500 Physician

While they sound like a lot of fun I do not think they are safe. For patient safety I believe in maintaining the highest medical standards. This means administering Botox in a safe clean clinical setting with no alcohol involved.

Many women enjoy getting cosmetic procedures at the same time as their friends, to make the experience more communal. However, these procedures should always be performed by a qualified and well-trained professional with years of expertise, ideally in a medical office setting. Botox is a neuromodulator that relaxes muscles. If injected incorrectly, it may create nerve damage and/or unwanted paralysis that can disfigure facial expresses and cause a drooping or closed eyelid. Botox takes three to four months to wear off, so if a mistake is made, you will have to live with the consequences for quite some time. If you and your friends wish to do Botox together, be sure to choose a board-certified dermatologist to help you get the results you want. We have performed Botox and other procedures with groups of friends in our medical office during the weekend or on evenings by special request.

 

It is absolutely essential that Botox is administered by an experienced medical specialist to help reduce possible risks and complications that can occur. Some forms of side effects can last weeks, while others can last for several months. If the Botox party does not have a medical practitioner performing the injections, then it should be avoided.

 

The person administering the Botox must have a thorough understanding of facial anatomy and how to work with these principles to not only make necessary corrections, but also to ensure a sound aesthetic result.

If your Botox party is hosted by a qualified physician who is using the real product (not lab Botox or other substance) you should be fine. I don't do Botox parties because I meet the patients, examine them, take photos and consent them.
This way we have a proper medical record for future treatments and if a problem were to occur we can figure out why. My only real worry is the horror stories of people going to a hotel room to one of these parties and having who knows what injected by some shady character and patients have a bad reaction to the substance without any way to track down what happened.
Hope this helps.