Hello, a little while ago used a third-party service called makexyz to print out a helmet for a Doom Slayer Cosplay. The Thingiverse model is here. Pictures of the helmet are here.

In retrospect I maybe should have asked for more infill, maybe a finer filament, used a smoother model but this is what I have to work with. As you can see there are many visible vertices on the outside among other little imperfections. I would prefer a smoother shell. This is what I'm shooting for.

I planned to smooth it out by sanding, plugging any holes with wood filler or bondo, then sanding again. As is evident I've already wet-sanded (400 grit 3m WetOrDry) at it a little already, but I don't want to do anything I will regret later without the input of more experienced people, as the print was very expensive. Do I have the right idea? Should I resort to a more radical solution like acetone? (it is ABS, printed using FDM process if that helps.) Or will I have to live with the jaggies?