Can you pop out a dent that has been repaired with bondo?

To me, it seems like whoever repaired it the first time, didn't do it right by relaxing the metal. Any time metal bends to a point beyond it's elasticity, it stays or "remembers" where that point is. If they didn't reset its natural position, then even siting out on a hot day could do that. When you dent a panel, you stretch the metal. They should have shrunk the panel around the dent to "pull" it back up. There are loads of reasons it could have appeared but one thing is certain if this is an old problem that resurfaced. it wasn't done right to begin with...

So, what to do?

Well for starters, i think you should assume the paint isn't going to survive the process. if it does, bonus. Don't start our thinking you can fix it without damaging anything, assume it will get damaged, then try not to. I say it that way because if you start by trying to NOT mess up the paint, it might keep you from doing the "right" kind of repair and taking some shortcut that will only cause problems again. What's the saying? Buy once, cry once?

Is it single stage paint? If so, you might be able to get it fixed properly fairly reasonably.

Personally, I look at PDR like I so snake oil. I know somewhere someone will disagree, good for them. I've seen too many "bad" jobs from hail damage that are visible on a hot day. That said, there's probably someone who is a fricking metal working genius that can do it, but I've not seen/met/heard of that person. Small dent, maybe.... that dent? No...

Metal "moves" and stretches like playdough, that's why we get dents.... to fix dents, it needs to be moved back, with force...