A small hole is not a problem. A small hole that tears (or suddenly goes "BANG!" and opens into a split the size of the panel) is a bad thing.

Clear packing tape is better than nothing if you don't have a color-match bit of Monokote or trim. I keep a small roll of "hatch tape" in my flight box for emergency field repairs.

Good place for a decal, too. Club emblem, Stars and Bars, etc.