There are a few ways to tell if your phone has been corrupted. One way is to check for unusual or unexplained behavior. If your phone starts acting strangely, or doing things that it normally doesn't do, it may be corrupted. Another way to tell if your phone is corrupted is if it won't turn on, or if it turns on but won't let you do anything. If your phone is displaying strange error messages, or if it seems to be stuck in a loop, it may also be corrupted.
If you think your phone may be corrupted, the best thing to do is to back up your data and then perform a factory reset. This will erase all of the data on your phone, but it will also hopefully remove any corruption.