Leaky Tub drain and rough fiberglass

After about 18 years, I have deleveloped a leaky tub outlet and it wiped out the ceiling in a closet.

When replacing the outlet drain etc I noticed that the fiberglass around the outlet (under the tub) was pretty rough and not really flat....one pretty big bump.

Should I try to sand down the fiberglass or just hope for the best with the rubber glasket?

I have no interest in replacing the entire shower.

Thanks

The rubber gaskets are forgiving...yours held for many years... but it would be a good idea to take a sanding block and some 120 grit to smooth it out.

The bottom surface of the tub IS the watertight connection when the gasket is compressed between it and the drain fitting. IF it is NOT flat/smooth, it CAN leak.

Thanks guys, I appreciate the feedback.