Hi Elliot,
Just for future reference, chose a cam for the slot that is not a snug fit. Otherwise this will happen, but you already know that.
At the same time, you do want the cams to be closed a bit otherwise they won’t be acting properly. Of course that makes them look like they will move and often they will, so you need to be aware of cracks that close up, because if the cam walks in, you may have problems getting it out, which is why you need to aware of your quick draws and slings, making sure there is enough slack/floppiness so that the rope doesn’t move the cam about.
When you go back there, sit comfortably in your harness with at least one nut key, two may be useful. You may be able to use the nut keys to gain purchase on the cam trigger if that is part of the problem. You may also find them useful to actually pull on and manipulate the cam lobes themselves. It takes time and patience. Be gentle. Be a little careful sitting in your harness. Make sure you move your legs often, if you can stand or semi-stand that would be better, sitting motionless in a harness is not good for you, reputed to be potentially lethal, which is why of course if your climbing partner gets knocked out, you don’t have very long to get him/her down safe.
Cheers,
Toc.