Not sure what cave you're talking about, but if it's one of those you have to jump into, there's usually a way out at the other end. See if you might have missed any cracks in the wall somewhere.
If your looking/facing the door you can't enter, there is a exit on the left side of the wall. I don't think it is possible to climb back out the way you entered.
I found door but couldn't find my way out. My game crashes if I try to swim so I hope it doesn't involve swimming. Any tips on how to find my way out? I have tried a few times and end up crashing in water.