If you know where or what part of your leg was first wet that should give you a starting point of where the leak might be. I have used UV wader repair for a fairly large hole caused by a clouser minnow.
The UV wader repair worked out just fine, I have not had any water seeping through thus far.
I have also used silicone on the neoprene stocking on some old waders, they had a hole somewhere in the toes, I could not pinpoint where the hole was, so I added silicone to the entire seam in the toe area, that worked out great as well not another leak. Hope this helps out.