Bald patches/dry skin

[I <3 Hamsters]

Hi there,
I have a pair of male dwarf hybrid brothers, Bean and Bandit, their age is unknown as they’re rescues but I recon they’re relatively young. Today I have noticed Bandit has some thinning/bald patches on his hind legs (in a similar place to where syrians have scent glands). Upon closer inspection all the skin around this area is white and looks very flaky/as if it has kind of a powdery white substance covering it. Bean seems completely fine, no skin issues at all.
They did have a squabble last night as they sometimes do and Bandit is usually the more submissive one, I wondered initially if the fur loss could have been a result of the fighting however the skin doesn’t look red or sore at all and they have never actually hurt each other in the past..
I made the mistake of putting some vaseline on his dry patches, he immediately went and rolled in his sand bath and coated himself in sand, I then tried to clean the sand off him and now he looks like a horrendous bald drowned rat. He seems happy as ever though!
Any advice as to what could be causing this and how to treat it? in the midst of the corona virus situation I need to get out and buy any medication needed asap before we are fully locked down.

Many thanks!

[cypher]

It's hard to know what might cause it unless there's something in the cage he could be rubbing against, it doesn't sound like it's a result of fighting.
The best thing for dry skin is some extra flax seeds (linseed) in the diet, a pinch daily is fine & evening primrose oil, a drop a day on food.
If they are fighting it could escalate at any time & one could get very badly hurt or worse so you should really think of separating them & if Bandit is the submissive ham the stress of living with the other won't be doing his health any good generally.