Hi I'm 17 and have a fairly large lump or spot on the skin of my penis,its bright red and quite sore to touch,I think it could be a sti but I'm not sure and I'm quite worried about it,anyone know what it could be?

It may be nothing more than an ingrown hair. But to get an accurate diagnosis, you must go to your doctor.

I don't know if you are sexually active at your age, but it could also be a STD.

Please make an appointment with a male doctor to get this taken care of.