hmmm, when i had a similar reaction to a medicine, went to emergency and they had me take benedryl. since it is over the counter and mild, you could ask if safe to take after tx and then try taking it - if it helps then you would know it was an allergic reaction??? or speak to docs and have them figure it out.

Kinda important to know if it is an allergy to the meds because if it is, the first reaction will be mild like this and next time can cause much more severe reaction, so you want to get to the bottom of it. i have had similar with rocephin, which is an antibiotic. i looked like a tomato in the lower face, neck and chest area and the rest of me was fine. ... so do find out hon, it is important...