New bf, during and after sex i have intense burning that has lasted up to 3h. no condoms used. last bf no burning. what should i do?

Lubrication: There are a number of reasons for the burning feeling you get during and after sex, such as insufficient lubrication, vaginitis, possible semen allergy, or a change in the pH of your vaginal environment. You are on an anti-biotic, so a visit to your healthcare provider to rule out a urinary tract infection may also be required if you develop pain with urination.