relax and enjoy your holiday, try on 30th aug to fly malaysia as I see no papers are torn out, just water erased stamp, I think you should be fine, if not you have option to flyback home
If you are flying back to India or home country, go to embassy to get emergency doc to fly back,If this is just thailand immigration stamp erased, they might have details in system so you may not have any issues, all depends on immigration officials
If u show onward journey ticket, they ask you for visa for that country as well, if u r from visa waiver countries then your fine otherwise you need visa too