Chosen Solution
While fixing my phone , I accidentally made a small dent at the top-right corner of the battery. Its almost unnoticeable. After multiple streak of bad luck I decided to let a professional fix it. He said that the battery started to expand(it is said because I played while charging[which is true]).
I’m a bit paranoid so , did the small dent cause it to expand? and/or is it safe to use for at least 3 month?
If the battery has started to expand it is not safe. You need to replace and dispose of the damaged battery and get a new one. Those batteries can explode and/or catch on fire and should be handled with great care.
