Not sure if this is the place for hardware repair stuff, but can’t find a community for that, so… yeah.
It looks like the dremel slot is too wide for a screwdriver to catch on. (And also ow, marred the back panel. Not much we can do about that.)
Might try the rubber band thing? That’s another trip to the store, but fortunately rubber bands are pretty cheap…
(the laptop works fine, we just want to upgrade the SSD)
– Frost
Search for “spiral screw extractor” at your favorite hardware store. They’re a godsend, even for small laptop screws.