OP, whats your cleaning solution? Also slap a 4 inch square of eternabond over that hole. Worked for a few poplar branches that poked holes in my Jayco!
I would think that nk your concern would be on the roof…
If there is already water in there, you can slap a sewer vent over it temporarily to allow moisture to escape. It might even turn into a permanent solution.
As a bunch of others are saying….eternabond. Clean it up, scuff it, stick on the eternabond and use a roller tool (if you have one, otherwise just your fingers) to adhere it.
It’s a permanent solution that will outlive the trailer.