Why is my phone boot-looping?

I had my back glass replaced at a local shop and noticed he forgot a sticker in the camera. I took the phone back, he opened it up, removed the film and realized he also forgot to put in a screw to hold the flash part in place. When he put it back together, he used a clear liquid glue around the edges, clamped it and sent me on my way after a few minutes. Now my phone is boot-looping and it's only getting worse. Went from every 10 minutes to 5 minutes and now it's every 3 minutes. What can I do, or should I do? what could be the problem? I don't want to go back to that repair shop because he didn't seem to know his was around newer phones either. I don't know if it adds to the possible reason this could be happening, but he used a generic back glass as well, no iPhone logo. (I don't mind it; I just know apple doesn't like aftermarket parts.) If anyone can help me, that would be awesome. Thank you.