回複：H1B 墨西哥申請簽證，請教！急！！在線等。。。

1. Not good for you, because your prior status is B before you changed to H1. For those who changed from F/J or H4, very good chance for success.
2. need an appointment
3. technically you can't return to US if rejected, but it is very easy to cross the border using I-94 because too many people waiting to cross so land post officers don't have time to check about you, if you don't tell them voluntarily.