Big blisters sore and swollen after 3 weeks after lip fillers with juverderm .

I would definitely followup with your injector ASAP and ensure that they follow you closely until this is resolved. You might require anti virals, potentially a steroid taper and possibly reduction of some of your filler. I hope this information is helpful for you.Stephen Weber MD, FACSDenver Facial Plastic Surgeon

Do you have a history of cold sores? If you do, how often do you get them? This should be part of your standard medical questionnaire for filler injections. See your doctor ASAP to get Valtrex as you don't want to get permanent scars from a preventable herpes outbreak.

As the others have stated, this is herpes of the lips and needs Valtrex soon. This was caused by the sun and the filler. You need to see you doctor to get treated. The filler also looks a bit wonky and might need to be removed.

Hello missyminx,Based on the picture you appear to have a herpes outbreak (also known as cold sores).  This can occur anytime after trauma to the area around the lips whether it was a filler such as Juvederm, Botox, or chemical peels.  They can also develop with stress.  Avoid rupturing the blisters as this can lead to a different type of infection.  There are pills and topical creams you can receive to help the outbreak go away faster but this can be discussed with your medical provider.  In the future, you may consider requesting an antiviral pill before receiving any treatment around the lips to help minimize the risk of this occurring (but it won't make that risk zero).  I hope this helps and good luck.  

This could be herpes simplex(cold sores, fever blisters). These can have multiple triggers. Sun exposure is a very common trigger. While injury can also do it, it would be unlikely 3 weeks after Juvederm injection. Anti-virals like valcyclovir can be used to treat this. If it recurs frequently, valcyclovir can be used to help prevent such recurrences.             jlr

If you are prone to a viral herpes (cold sores), you should take an anti-viral when having lip injections.  This appears to be an outbreak.  See your injector for medication and follow-up.

That appears to be a herpetic outbreak. Many people who have this will have an outbreak after fillers and/or sun exposure. Outbreaks can be prevented with a daily Acyclovir pill, but if you don't want to take it daily I would at least suggest you take it before lip fillers or a trip to the dentist. "This
answer has been solicited without seeing this patient and cannot be
held as true medical advice, but only opinion. Seek in-person treatment
with a trained medical professional for appropriate care."