Your internal Lithium-ion has battery expanded!
Stop using that iPad IMMEDIATELY1
Get that iPad out of your housse, ASAP.
That iPad is, now, a serious fire risk!
Put it outside somewhere away from your home and where it can't get wet, until you can return this iPad to your nearest, “local”, nearest Apple Store location!
Use the “Get Support” link, at the upper right hand corner of every Apple Support Community Webpage to attempt to schedule an appointment with your nearest Apple Store location to get rid of this iPad, now.
Apple Store employees will be glad to help/assist you.
Sorry & Good Luck to You!