How to remove dried hot glue from a closed door?
Carefully cut as much of the glue as possible with a utility knife. With a small pry bar, cats paw, or flat bar gently pry at the gap. If you can, cut some more glue while prying. you may also consider wedging  a paint scraper,( not to be confused with a putty knife) in the gap, then hitting it with a hammer.  At this point you have to weigh the risk of damage to the door opening against maybe burning down the house melting the glue.