If you're going to the loo that much it might be that you're wearing away the skin down there with all the wiping - try maybe patting dry and seeing if it goes? I'm only using the loo 7-8 times a day, maybe up to 10 times, so haven't had this, but I'd imagine the more I went then the more I'd be wearing away the skin there.

I hope it is just paranoia and that you're fine!

BTW, I get green stuff - at least pink is a more normal colour. Maybe you'll get some green next week and that'll start off a new worry?