Some people let things get them down, like a board falling off of a roof, or a flat spell, or onshore winds. But there is no reason to let such small negative things dictate your life. Stay Above it. Stay Above the Weather. PFS
If thats the route you wanna go, i'll give u some more pointers.
now it's not gonna be like putty putty, little thinner than bondo, but thicker than topcoat.(if you're familiar with auto body repairs) tape will be your bff, and its gonna take buidling it up, sanding it down, building it up, sanding it down, till you get the form right.
Make like, a pocket out of tape, it prob be easiest doing it with the board vertical, tail in the air, use as much tape as u need to create a bowl/cup/container for the crap, without it being to large in terms of width or thickness, keep it as close to the shape of the board as possible. once it's hard, remove tape, and start sanding. It's pretty easy to sand, not as easy as foam, but not as bad as pure glass. Just make sure you clean up the damage real nice like, get rid of floating chunks etc. before you start. goodluck. here's an example pic of one i did, not tail, but you'll get the idea