If you're repairing your iPhone you have about a 20% chance of shredding/stripping a screw at some point! Some of these are easy to get out but not always - check out these 2 easy ways that fix most issues up!
If the screwdrivers on that angle didn't work then you can try scratching a notch into the screw with a small flat head screwdriver. This can give you some more tracking then repeat the above process. Otherwise try the drill! Just grab a small drill big and dill 2/3 of the cap of one of them. This will allow you to use a normal screwdriver to turn the whole head by twisting in the grove (hope that makes sense!)
You could also try this great tip from damon691104: "Another way is to dab a little super glue on the screw and stick the pentalobe screwdriver inside the screw and allow that to dry. Then the glue will hold everything together making it much easier to turn the screw. You have to turn slowly at first so not to break the adhesion since its only a small amount of glue".
Also this tip from Sophie Galbraith "I really recommend tweezers! I couldn't get mine out the bottom of t phone at all, but found after trying all the things listed here, getting tweezers around the slightly raised screw was the only way to get it out!"