What is normal to feel 24 hours after Botox in jaw?

what you might be experiencing is some tenderness from the muscle and inflammation from the site of injection. You can take some tylenol for discomfort if needed. This should subside in a couple of days.

Thank you for your question.It can take Botox up to 2 weeks to start working.  The tightness you are feeling is probably more related to the grinding and clenching of your teeth that you do at night. The area may be a little tender from injections at 24 hours, but Botox will not have taken effect yet.

This can be typical and should resolve in a few days. If you're concerned, I recommend following up with your Doctor. Keep in mind, it will take 1-2 weeks for final results with Botox. Best, Dr. Emer

I am a big fan of arnica to help minimize post-injection symptoms. Arnica Forte is affordable and comes as a capsule and a serum. Next time you go in for injections, start the Arnica Forte two or three days prior to the injection and serum over the location you are going to have injected. 
keep in touch,
Kimberly Cockerham, MD

It's too soon to see the effects of the Botox treatment to the masseters. The tightness you are feeling is probably related to trauma from the actual injections which can result in some swelling and bruising. I would give these symptoms a few days to resolve. 

There may be some swelling from the injection process so wait and see what it feels like in a few days