I am not assuming anything, but a sort of close look at the pic, to me suggests that this rip isn't new. In fact, by the look of the trim on the side, it maybe hasn't had much tlc in the past. Did you just buy this rig? Not that it really matters, but that pic looks some ugly to me and just putting some tape over it and sanding and painting isn't going to make this whole again.
Could you fix it? Sure, as has been observed, if you have a place to do it and the skills. That skin has to come off right to the seam on the roof and then all the way under the cab. You'll need to address any wood rot, as I had mentioned. That means tearing out and replacing and damaged wood and insulation. Plus, if there is any rot under the skin, I'd bet that it is in the inside as well, in the bunk area. If you don't do this yourself then it's an RV shop then you are talking a whole bunch of money.
If you can find a handyman that knows woodworking to help you? That's be a good way to consider going. It's not rocket science, but if you don't do it right, that will just fall apart.
Gary Haupt