Not too much moisture would have got past the oil, but that which did will now start to diffuse throughout the instrument. In a few hours, we take it out, play for 10 minutes, dry and put away. Again some moisture gets through, but has time to diffuse before the pressures get too high. This is the principle behind breaking in a woodwind instrument. If you notice that the inside of the instrument has got rough, this is worth fixing up.
Condensation gets past oil and raises grain.
Corrugated surface holds water better so more water gets past oil, etc. Rather, get a length of dowel and some fine steel wool. Wrap the steel wool tightly around one end of the dowel and use it to smooth the bore. This is made easier if you have some way of spinning the dowel, eg in a lathe or drill. Don't try to iron out every corrugation - you will end up altering the bore.