iphone 13 pro battery very bad my phone only 27 days use after check my battery health 99

That's absolutely normal, bearing in mind two things:

• That value it's approximate (it can be now 99.9%)
• That value is relative to when the battery was new (most likely before September 2021, when the iPhone was manufactured).

Start worrying when that value is close yo 80%.

Regards

Giulio