You need to sand a bit to see what happen inside. mandatory. And also, the epoxy dont glue well over the paint/gelcoat, thats why you need to sand.
Recently my mas hit my FUTura, and a fine crack. After sand i saw the problem was only paint and the inside layers was fine.
Some liquid/fluid epoxy to seal it and sailing again. But mit hit was between the white/black/red colors...