The frame on the left of my eyeglasses is a little loose from the lenses will it still hold?

There's a little tiny screw, (usually), on the bottom of the earpiece stem that holds the frame to the lens, close to where the stem of the earpiece connects to the eyeglass.

You need a special screwdriver designed for eyeglass repair to tighten the screw. If the screw has fallen out, it needs to be replaced. An eyeglass repair kit is needed.