I just arrived in Thailand with my non b multi (1 year). Immigration stamped me in for 30 days exemption so I had to go back and they corrected it to 90 days (he even showed me the date in the computer) but what I want to know is if he forgot to stamp "used" on my visa. They have precisely did that in all my past visas. Do they stamp used in this visa or not? Do I need to go to immigration and really check he I am my non b visa or not?