Hi Pablo, just to let you know we've passed your question onto out team who will endeavour to answer as soon as.
Ouch- poor Nano! It is always hard to tell what has caused a scab just by looking at it. Your veterinarian would have probably asked you numerous questions that would help them try and piece together what may have happened/caused it in the first place.
Skin lesions can occur due to many different things and a biopsy is a good step to help reveal what is causing this scab in Nano. In the meantime, keep a close eye on him to make sure he doesn’t traumatise the area and make it worse, as he could then end up with a secondary infection and require medication.
I’m sure the results will be back soon and then the appropriate treatment (if required) can be started.