How To Treat Small Growths On Penile Shaft Which Looks Like Skin Tags?

Hi, I have a few small growths on my penis both on the shaft and where the skin meets the head/muscle. I assumed these where skin tags as they developed long after I last had sex (I was checked for STD's too so that can't be the cause). I have tied them off and all but the base died and fell off, but they seem to regrow in the same place as I can never quite get the bottom tied off. Could I have your advice please?