Either a jock itch or an STI can cause groin itching. Jock itch results from sweat and friction, leading to redness, itching, and rashes. An STI may have similar symptoms but is related to unprotected sex. Use antifungal creams for jock itch and practice safe sex to prevent STIs. Maintaining good hygiene is also important.

Your boyfriend may have a severe skin infection that’s spreading. The redness, swelling, and pain—coupled with swollen glands in the groin—indicate that it might be a bacterial infection. To cure this, he may require a course of antibiotics such as penicillin or cephalosporin which can help to fight off the infection. It is important to seek medical attention as soon as possible to avoid further complications.

Your skin issues se­em to indicate pimples and sore­ bumps. These happen whe­n pores get blocked, trapping bacte­ria inside. An over-the-counte­r cream or gel with benzoyl pe­roxide or salicylic acid may help. These­ ingredients reduce­ inflammation by killing bacteria on your skin's surface. Wash your face re­gularly to prevent clogging. Don't squee­ze pimples, though - that can cause scarring. With some­ care, those bumps will clear up.

It is uncommon, that Bactrim might cause a yeast infection. This happens because the good and bad bacteria equilibrium in the body can be tipped by Bactrim thus allowing yeast to thrive. Among the symptoms are itching, redness, and a thick discharge. Probiotics and antifungal medicines can be used to cure this. It’s also a good idea to talk with your doctor about other possible medications.