[SKB_Hamsters]

Surolan is a prescription medication so only should be used on vet instruction, so would strongly advise not using it in your hamster ear unless a vet tells you too. Surolan is prescribed to treats fungal infection so would doubt with him having a red ear that it was fungal (but I could be wrong) plus would be careful in applying it to the skin being a steroid treatment as it can thin the skin.

There is a chance it could possibly be ear mites from your description - which you can buy off the shelf mite treatment (beaphar hamster spot on which is a ivermectin). So you could try this and if no improvements/worsen get him seen by a vet.