I Have mounted about 100 deer and always had problems with the lip line opening. I always thinned the lip line and cut a small slot, glue, but found out the issue is the skin is actually pulling the form of the mouth ever so slightly and creating a gap around the lip line. The skin is not leaving the slot but pulling the mouth of the form open ever so slightly. Then I have to epoxy and repair. Any ideas how to stop this would be appreciated. I use a rub on tan and shave with a fleshing machine.