Bulging from back of phone

[Trish+H]

My phone has always been in a phone cover and never been damaged or got water in it but I noticed today the cover wasn't sitting right. When I took the cover off the back of the phone is bulging out of the casing. Anybody else had this?

[daveNOS]

@Trish+H That's usually down to the battery swelling from overcharging.

[PandJ2020]

depending on the case it could be caused by overheating - you'll find case manufacturers advise to remove the phone from the case when charging (however impractical that can be)

It may not be covered under warranty.