It is possible you did damage if the plug was forced out by having too much oil in the cylinder and it hydraulic locked and blew the plug out. Was there a lot of oil blown out as well? How much did you put into the cylinders and why? Was it only the one plug? How far was the plug installed? If it was in there to the seat but not tight it takes a lot of pressure to blow one out and was much more likely to have done damage.
To test if there was damage would take some specific testing. Namely a leak down test and using a CC test to determine if the piston is farther down in the cylinder. You may be able to see it if you ran a compression test with the engine running but even then it would be hard.
If it has been damaged but still turns over freely I would install the plugs and see what it does. Then see if you can do a running compression test and see what numbers you get.
Saturday, June 2nd, 2018 AT 9:15 PM