ipad pro horrible battery swollen

If your battery shows any sign of swelling, such as displacing the iPad screen, you should stop using it. Do not attempt to charge the iPad.

You would be best advised to visit the Genius Bar at your nearest Apple Store or Apple Authorised Service Provider (AASP) - where your iPad can be assessed by Apple Technicians and appropriate arrangements made.

For practical purposes, in lieu of repairing and returning your own iPad, Apple usually exchange the iPad for a renewed/refurbished iPad of the same model and specification. The cost of the exchange is the same as would otherwise be charged for repair. Unless you have benefit of an active AppleCare plan, an out-of-warranty repair while expensive will be somewhat less than the cost of a replacement iPad. In-warranty, your iPad will be fixed without cost.

As for out-of-warranty repair costs, Apple offers a fixed-price price repair. You can verify eligibility and cost for your region/country here:

iPad Repair & Service - Apple Support

If you have an active AppleCare+ plan, the cost of repair is reduced to a small excess/deductible fee.