Bald patch.... Tumour?

My rabbit has a bald patch of skin next to her 'bottom/ urine area.' It has what I feel a bone under the skin and the skin has lots of veins in the skin area. I'm hoping it isn't a tumour (I don't think so as it is skin level). My bunnies are moulting like crazy!! Is it just that even though it's Autumn? My bunny is four and a half and isn't neutered also female. Yes I know the risks of cancer. What do you think it is? What should I do? Lots of my family are vets so should I send them a picture? Please help as I love her so much and would do anything to spot things early! I can always take a picture tomorrow and attach it if necessary. Thanks

A picture would help, and I would definitely send it to the vets in your family, they would know better than us pet owners. The best option would be to locate a rabbit savvy vet and have them examine your bunny though!