Is is between the beams ?

If so I wouldn't worry too much about it. I'm sorry to see a dimple in your new hulls, that is for sure. But if it is between the beams then the loading in that area will not be such that the dimple is of any major significance. In this case just go sailing and regulary check the area around it, keeping an eye on it. If it ever delaminates then I feel the repair is straight forward enough. The specifics of the repairs in not my speciality, but quite a few people then just drill a small hole in the outer class layer and inject some epoxy resin to retore cohesion between the class layer and the compressed foam. But a professional repair is always an option as well. Personally I've seen many boats with such dimples last for years and years as long as the area around it feels solid (no delamination present).

Wouter