Filler didn't harden - now what?

I just spent a couple hrs scraping and sanding. got all off except lots of little tiny low spots. it was soft on top, but after I scraped that thin layer off it was just hard enough to sand (thank God). i used an angle grinder on the thick spots cause the sanding discs packed up so fast.

I'm thinking a layer of fiberglass resin might be good now, to fill pinholes and seal up the tiny filler spots. i cant possibly pick them all out and i don't really want to do that much sanding cause it would thin the glass quite a bit.

also - i didn't use acetone and I think it might attack the fiberglass anyway.

Here it is. the light spots are all filler. seems hard enough to sand so maybe i'm ok to build on top of this now?

i just put a layer of resin on. seems ok now