3 weeks ago I had Botox under my arms. My pits have been burning a little and feeling uncomfortable. Not sure if this is normal?

After 3 weeks, this is unlikely due to your Botox treatment. However, I recommend following up with your injector. Botox results resolve in 3-4 months. Hope this helps.

Common side effects of Botox include: Pain, swelling or bruising at the injection site. However, since it has been 3 weeks now I would recommend following up with your injector to be evaluated or getting a formal evaluation with an expert. Best, Dr. Emer

Hi Astraea19, thank you for your question. I'm sorry to hear you are experiencing discomfort and burning. Side effects from Botox include irritation at injection sites, however this should not be present 3 weeks post injection. I recommend scheduling a followup appointment with your injector to examine the burning and discomfort. 

Three weeks after the treatment, the sensation you are feeling is probably not related to Botox. But you can always follow up with your treating physician to be certain. Good luck from New York City