I had a problem with a piece a few years ago that had dozens of hairs coming through the underside.. I twas really annoying. U could try to pull it through to the other side, but its pretty tedious and probably very difficult. I just let it be, and it annoys me i just pluck them out.

The only time its really a big issue for me is when it happens at the front hairline going through the very front of the lace.. reason being.. if i try to comb my hair up .. or spike it.. i try to get all the hairs going up and ill pull that one hair and its really underneath the lace and wants to lift the lace up