hmmm, if it's a saddle sore, and given the location, it could be occurring because (a) knicks need to be cleaner - try washing in HOT water with an antibacterial rinse in the machine; or (b) bike set up - may need adjusting as you're not sitting properly on the bike; or (c) your hips or body in general is out of alignment which also means you're not sitting evenly on the bike. In which case, if you find the problem recurs in the same area, go to a chiropractor, physio or osteopath to get put back into alignment, and keep up the antiseptic etc in the affected area.