Could really be anything from psoriasis, eczema, seborrheic-dermatitis (as said above), bacterial infection, fungal etc etc. All i can say this problem is coming back once in a while, although it has never looked so ugly.
The morning after my OP, the crust partially dissolved into a White Yellowish grease that i was able to clean, then the crust reformed later. I could feel a small open wound behind the grease. Not sure i can put any cream on that without risk.
I feel better atm, it's still there but my hearing is almost completely back.
I have an appointment in few days to see a dermatologist. Will see if it has cleared up or became worse....