Something really concerns me about your post - you stated you got him last week - he has these blisters on those five scales and is now starting a slight wheeze (an indication that he may be developing an RI), BUT he gets along well with your other BP.

Does that mean that you have chosen NOT to quarantine him for three months from your established animals? Or were you not aware of the importance of quarantining new animals? Especially one that may be sick and can get your animals sick?

I'd definitely take him to the vet to get both the scales and the wheeze attended to, and do NOT handle your other animals after you've handled him.