Heat. Use a soldering iron tip and rub against the trace until the solder mask separates.

The wrinkled areas is actually solder underneath the solder mask. Looks normal.

Now the area on the lower left definitely looks like corrosion.

I would suggest applying a surface treatment afterwards. You could either apply solder to the copper, or you could use a clear polyurethane paint to seal it. Just make sure you have cleaned it thoroughly first.