The heat is apparently staying a while. That's the whole weather report. Ask the weather folks for the rest.
Here's the part I care about. Every time it stays hot like this, I start getting the same text from Vista: "my screen is lifting up at the corner, is that bad?"
Yes. Lovingly, yes.
What's going on under there
A phone screen doesn't lift on its own. Something is pushing it. In a hot stretch, the something is usually the battery. It got puffy. Lithium batteries swell when they're stressed, and heat is the stress they hate most, especially an older battery that's been riding around on a dashboard or sitting in a sunny window at an office off the 78.
Swelling pushes outward on whatever is closest. Up front, that's the screen, so you see a gap at one corner, or the glass sits a hair proud of the frame, or touch gets weird along one edge. On a phone with a glass back, it can be the back that bows instead. Either way, your phone has a belly, and that belly is a battery.
Please do not squish it back down
I know the urge. It looks like it just needs a firm press, like a sticker that didn't stick. Don't. A swollen battery is a sealed pouch of stuff that does not want to be poked, bent, or pinched. Pressing the screen down pinches it. Same with a case that's suddenly too tight, so take the case off if it's fighting you.
Also skip the freezer. Someone in Vista always suggests the freezer. Cold doesn't un-puff a battery, and it adds moisture to a phone that's already open at a seam.
One thing worth sorting out first: if you dropped it last week and the corner came up right after, that's probably a bent frame or loose adhesive, and the battery may be fine. The swollen-battery tell is a lift that grows over days with no drop to blame, and a phone that feels thicker through the middle, not just chipped at one corner.
What to do instead
Stop charging it. Charging makes heat, and heat is how we got here. If it's off, leave it off. If it's on and you need to grab a few things, back up your photos, then set it down somewhere cool and hard, not in a bag or under a pillow where it can't breathe.
Then get the battery swapped. That's the fix. Not a screen reglue, and not waiting to see if it calms down. The screen usually sits back flat on its own once the puffy battery is out and a fresh one is in, as long as the glass didn't crack while it was being pushed up. If it did crack, I'll tell you that before I touch anything, and you decide.
I come to you. Vista, San Marcos, wherever in North County you and the puffy phone are. I'd rather drive over than have you drive around with it sliding across a hot seat.
Why it's showing up now
Batteries that were already a little tired get pushed over the edge by a long hot spell. The phone that was "fine, battery's a bit meh" in June becomes the phone with a gap in October. Hot car, hot pocket on a walk, and a charger plugged in on top of all of it. That's the recipe.
A stretch like this and I'm basically a swollen-battery specialist. Not by choice. The heat picked it.
So: screen up at the corner, or a case that suddenly doesn't fit. Don't press it. Don't charge it. Send me the make and model and where you're parked, and I'll bring the battery.