I should mention that in the "post-pop" photo it looks like there's something in the middle, and there was. It took a few days but I was able to get that plug out, since I thought that was contributing to the non-healing. I don't think there's anything in there now, but I'm worried that if I tried to find out, then I've just make it worse.
If you had left the plug in, it would have continued to fester.
Now that you have managed to get the root of it out, it is able to heal.
Is your chin and surrounding area still red like on yur photo? If it is there is still an infection. If not, then it has healed, but you will be left with the lump. It may fade and get smaller in time, or it may fill up with rubbish again.
You can use an antseptic cream like germolene or sudocrem or something similar.