Thanks for using Petco Pet Education Center, formerly Petcoach! This looks like very severe allergies or a condition like mange though other possibilities like immune mediated disease still have to be considered. This can be differentiated based on physical examination and basic diagnostics. This must be really painful and for that reason I highly recommend that you have Callie evaluated by a veterinarian for further assessment and treatment as soon as possible. Her decreased appetite is likely due to discomfort. They would be able to check for these possibilities and most importantly, treat her accordingly. If she has been scratching at her eyes, I highly recommend using an e-collar to prevent further self trauma. Good luck and have a good night!