Screen fell off - what can I use to reattach?

I used B7000 glue for mine, it works good for stuff like this. Although for me it still fell off again after several month :) I fixed it again, but in the end I just upgrade to Amazfit BIP 2 recently.

Mine just fell off as well. I’ve had it for over two years. I inspected it, and realized that it looked like the seal for the display has been de-laminating for quite a while! I am thankful I didn’t wear it while showering, or doing things while around splashing water. It woud have surely damaged it. I carefully scraped all the junk that had accumulated around the edge of the display, and around the watch casing groove for the display was. I used “shoe goo” as the glue. It supposedly has some water resistant properties. Hopefully it will work for a while.