I see.
I don't think Bloods are more difficult. If anything I may consider them easier since they don't need much more than rats which they will readily eat. The only thing that can make them a challenge is their size and the size cage they require. My big female is just over 5.5ft and weighs in at 30lbs. She can be a handful when she doesn't want to go back home but she is usually a puppy dog.
What skin issue does it have?