Huh has a good answer. Also…is this ’scab’ orange and crusty looking? This could be a fungal infection and it would explain the reason it is reoccurring. I really suggest a vet visit either way!

Tyler had one on his chin I asked the vet what it was and she said it she didnt know what causes it possilby ingrown hair or dry skin that doesnt heal very common there is no danger. I put neosporin on Tyler when it breaks open to keep it from getting infected and it heals pretty quick when I do.

Your ferrets may have mast cell tumors, the second most common skin tumor in ferrets. Contrary to mast cell tumors in dogs and cats, mct’s in ferrets are rarely ever malignant(cancerous). They do usually itch though and that’s what makes your ferret scratch and bite at the site of the tumor.
Mast cell tumors usually appear as flat, often hairless, small plaques on the ferret’s body.
Take your ferret to the vet to be checked. The vet may want to remove the tumor surgically. MCT’s do not usually involve the tissue beneath the actualy tumors, so the surgery is not invasive.
This is just a guess, but one way or another, get your ferret checked out.
Do you have just one ferret?

Good luck to you and your fert.