I would like to do away with shower doors and hang a shower curtain..How do I deal with screw holes in fiberglass shower surround? PLEASE HELP!!

Nothing will make them disappear. You can fill with fiberglass putty (Bondo), sand smooth with wet sandpaper and paint. Or try to find a dolor match gel coat to go over the repair. But both will show. You can also just reinstall some stainless steel pan-head screws in the holes or find something decorative to cover them up.

add a little to jaybees answer
put a dab of silicon on the end of your pan headed screw when you install. it will help keep water out of screw hole

I made my shower door, screw holes disappear (in tile) by mixing up some artist oil paints to the same color as the tile (small amounts, you just need dabs) till I got a really close match to the color. Mix tiny dabs of paint around a plastic plate, so as not to waste paint, ((and only oil paints, no craft acrylics will work)).
If your surround is white, that helps, just add a tiny bit of gray/brown to kill the bright titanium white? Mix up a bit of clear, two part epoxy on another plate, and add some of the matching paint to it.

Slightly overfill and push the mixture into the holes. Allow to cure for an hour or so, till fairly rigid, and then take a safety razor blade and scrape it off flat to the surround. With tile, it left a perfect amount of sheen when cured. With the fiberglass it may show a shiney spot, but the color will match.