What could it be? It is not an STD because I haven't had sex. I am circumcised (but haven't ever had this issue). It started lte last night. The only explanation I could have is early yesterday, I masturbated, then took a bath (not a shower) right after I was finished. Perhaps some hot water traveled inside? (I have no idea; I'm not a doctor.) It hurts anytime it lightly touches something, and makes wearing underwear extremely uncomfortable. It's only at the very tip. I cannot see a doctor until Monday. So, what can it be? Any advice or explanation is appreciated.