I got a fairly bad abrasion on my arm, and mistakenly put hydrocortisone cream on it instead of antibiotic. it has been three days and it's still pain?

Keep clean: If the abrasion is very deep , it may take many days to heal . Until a good scab is formed, you will likely have some pain. If it gets swollen or pusy, be sure to see your doctor. In the meanwhile, be sure to keep the area clean and change the bandage regularly. I doubt the 1% hydrocortisone cream you used had significant impact on the wound healing if used for just a day or two