Constant redness on my face?

Ever since i was around 13 or so i developed this redness on my face which never goes away. Sometimes it's worse and sometimes it's not too noticeable. it seems to get worse when i'm ill or had no sleep. It's not really bad or anything and i don't think it's rosacea as i went to a dermatologist when i was like 14 and i remember him saying it wasn't rosacea and he gave me medication for it which didn't work. I'm 19 now and i live a healthy lifestyle but this constant redness/irritation on my skin won't go away. Anyone have a clue to what it might be or something?
Constant redness on my face?
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