Taking it apart was nicely explained at ifixit!
https://www.ifixit.com/Guide/HP+Prime+Graphing+Calculator+G8X92A+Button+Panel+Replacement/137052
The little points on the three key's where completely squashed. And a couple of them where comletely bend.
I wanted to bend some back with hot air at 160 degrees celcius with a hollow needle. This went extemely well! Even better, the hot air caused the little points, that where completely squashed, to spring back in it's original shape withouth any help!
Only looks a little burnt, hope this hardens the points too.
It went so easy that i don't have any "before" photo's.
Hope this can be of good use for anyone with this problem.
