Our rabbit is in a heavy molt right now and ended up with a completely bald spot. Our vet didn't have any concerns as long as the fur grows back in, and it did really quick. They can look crazy when they have a lot of fur and they are in a molt. As JBun said, make sure to do your best to remove the loose fur. We have a glove that has some little rubber nubs on it that we pet the rabbit with and it removes the fur. Be careful about using brushes or other tools unless you know it's safe for the rabbit, and don't do it too hard. Some rabbits are more sensitive than others when removing fur. We have a few who don't care, but one of our rabbits is very grumpy when you mess with his loose fur.