Diagnosis Requested

Update: The discolouration stopped getting worse and spread no further so I'm guessing that it was down to getting water on the leafs causing them to burn. Just thought I should add this in case anyone else comes across this and wonders. Thanks for all your help.

I also am a newbie and was looking for why a couple of these spots were on my leaves. I also have been misting them, so NO MORE! Thanks!

washing leaves is fine, just shake em off, use the dish soap like was mentioned, or spray a bit before lights come on.