Do you think it's possible that you have Demodex mites and that is what you are treating? Your story sounds alot like mine with the grains of sand and having to see the eye doctor. That's what was causing my irritation and dandruff like stuff on my eyelashes and eyebrows. He gave me Xdemvy drops to use and then I have tea tree oil wipes for cleaning. I was already diagnosed with Seb Derm and I think they can go together.

I was originally misdiagnosed as having psoriasis but once my GP for pain examined me he corrected the misdiagnosed condition as Dermatist Seboreah. My eyes became inflamed so I was eventually referred to the VA Optometry as my eyes felt like I had sand in them and I would go through generic eye drops which helped.. The VA Dermatologist realized my eyelid pores were blocked by the oil my eyes produced and my Seboreah. I now start my day with a warm wet washcloth with nothing else but the warm water gently rubbing my eyelids in several directions then I keep wetting the washcloth to gently rub everything from my neck up using only the warm wet washcloth. Once I dry off everything I rub in medicated creams rotating to the next cream rotating them. The medicated creams are Desonide Cream 0.05%,
Triamcinolone Acetonide Cream 0.1% and
Ketoconazole Cream 2%. I use hydrocortisone cream on really bad outbreaks. My ears also get plugged with my earwax and Seboreah so I use a q-tip with some medicated cream to apply it inside my ear canal. If my ears get plugged I use earwax remover in my ear canal then put an earplug in and let it soak for a few hours to all night. I have a water-pick with warm water set at the lowest level and flush out my ears. Once my ear canals are dry I use medicated cream on a q-tip again. When the buildup inside my ears are really impacted I continue the cycle. I have removed plugs the size of the eraser on a pencil as well as numerous small grains of the plugs. I had this done several times in my GP's office before I realized I could do it on my own saving me a trip to my GP's office and all the lost time. If my ears still feel plugged and they hurt I drink hot beverages and take hot showers as well as using the earwax remover, earplugs and the waterpick. Good luck and check with your doctors about using these methods.