I get frequent blisters in my armpits and sometimes in my groin area. i usually just apply antiseptics, and they drain all by themselves after a while, but then they recur. what could be the cause of it?

Infection?: "Blister" normally means superficial, filled with clear fluid. I can't explain something like that. Maybe allergy? But if these are deeper bumps that drain pus, sometimes with blood, then you may be having recurrent staph or strep infections. Or maybe a chronic problem called hidradenitis suppurativa. See a doctor, preferably a dermatologist or infectious diseases specialist. Good luck!

Probably not: blisters, rather they are sebaceous cysts. (Plugged sebaceous glands at the base of hair follices) Washing your groin /armpits with an antibacterial soap may cut down on these! Hope this helps! Dr Z