Don't waste time looking for tattoos, unless you want a cool non-medical one!
I have several female friends with PWS...
(my wife for one!)
They are all expert at coverage makeup. Here you can see at this link (no I'm not selling nuthin'!)
Just click the LA lunchers link in the menu.
Joie, one of the coolest ladies around, just wrote an amazing book called "Marked For Life" about the very thing you are speaking of... not wanting to look 'gross'!
look online or at a bookshop or library. It's worth it! It really makes you think. Plus she writes a makeup section over at the sister site birthmarks.com That's the Steffano site. Lot of us over there dealing with the same stuff.
I hope you find some answers.
I can cut to the chase although you won't believe me...
You're just fine as you are!
See I told you you wouldn't believe me! It took me years to see past my PWS. Still have trouble some days.