Being tall helps on this one. Not gonna lie. If you can't reach the thumbdercling, you're going to either need to climb four grades harder or walk away.
Rain sucks, but broken holds suck even more. Remember, never climb on wet rock in Fontainebleau.
The sandstone becomes brittle, and pulling on it will ruin classic problems. Drying it doesn't help, because it's still wet and weak inside.
All you can do is wait for better conditions.