I Recently Gained A Blister 1cm Diameter On The Shaft

I recently gained a blister 1cm diameter on the shaft of my penis, it has scanned over, but now it has burst open.... What should I be doing? Never had sex, teen, does masturbate... Also I have had what appears to be fordyce spots on the shaft as well for some time (years), but the issues don't seem to be related... Thanks for any help, I can supply more info!