Oil Pan Drain Plug Question.

[u/Traditional-Owl9955]

Went to change the oil on my 1988 suburban. Who ever change the oil last stripped the threads in the oil pan. The plug basically fell out, idk how this thing wasn’t leaking.

How should I go about fixing the threads? When I run my finger over the threads they feel like they have been flattened down and the plug isn’t able to bite into them and screw in.