3M 5200. It will be permanent. We use it on boats above and below the watering. It bonds to almost everything permanently. It is very difficult to remove once set up especially if two pieces are bonded together. Comes in white and other colors. You can get it at home depot and I think Lowes.
There is also a fast dry version. It is where the caulk is. If you don't want something so robust then you can use 4200. It is more iv resistant, but the 5200, nothing really messes with it. I had a leak between the sleeper and the cab on the truck. I loosened the joining bolts and dumped the air for the sleeper to spread the gap. Squeezed the caulk up in there, tightened the bolts. No more leak. That was 2 years ago.
Your best bet, hire a vet! Please.