Pin holes in paint - The pin holes are called solvent pops. There was still oily residue down in the fiberglass that was brought to the surface by the paint solvents. Next time sand the hood back down to the fiberglass and wash the surface with TSP cleaner and hot water. TSP is available at hardware stores and paint stores. It is used to wash the oily kitchen walls and surfaces before painting. Bake the clean hood in the sun or paint booth for complete drying before sealing with PPG DP48 white epoxy primer. Then prime with filler type primer, wet sand and paint.