bluesguyjmb

You asked about trimming the front of an ultra thin skin.
I think cutting it as near to the hairs as possible prevents that 'curl' issue.
Don't be afraid to cut an irregular shape following the irregular line of the front hairs.
Also, using unsharp scissors can stretch the skin base as you cut it and that too can cause it to curl.
My recommendation would be to use a scalpel blade and even hold it at an angle to create a 'slope away' chamfer at the front.