I've tried melatonin in various doses but it did nothing for me. I thought I had an allergic reaction to some new medication which caused extreme itching on my back and torso so my niece suggested I try the Benadryl. The itching would subside somewhat at night but it really helped me stay asleep longer.
I still have the itching after switching medications so it wasn't an allergic reaction.
Itching, watery eyes have been a problem for me. Benedryl fixed the watery eyes. Freshly laundered sheets and blankets (clean of dog fur) resolved the itching.