You're either going to have to get a replacement bottom bracket now or you might not be able to get one later, at least not quickly or easily.

The Octalink bottom bracket is the old-style, inboard type meaning that it resides inside of the bottom bracket shell. As such, it is less exposed to water and other contaminants than the newer, outboard type of bottom brackets/bearings. Thus, if you make sure not to spray it with water or degreaser, it may last quite a while.

Worst case scenario isn't that bad. Your bb wears out. You can't get a new one. Just use a new-style Hollowtech II Shimano crankset or don't use a Shimano crankset, use something else. You'll keep riding either way.