Something is inside the oil pan of a 1988 Buick Century, 4cyl, 2.5L

My dad and I were working on my 1988 Buick century (4 cyl, and 2.5L engine) and we had to replace the crankshaft position sensor. Well, while tring to get out the ignition module (which it is attached to), part of the sensor broke off. With the rest of the sensor in the engine, we tried to get it out. We succeded in breaking it in half by drilling a hole in it and then putting a self-screw in it and pulling it out. However, the other half broke off and is now in the oil pan. The oil pan has an in-pan oil filter and we were wondering a couple of things. First, is it possible to get the sleeve/mount that the oil filter goes on inside of the drain plug off, as to get to the piece in the oil pan? Second, my dad was wondering with the piece inside the bottom of the oil pan if it would do any damage if we just left it in there. Any help would be greatly appreciated.

This is a very common problem (even more so on the V-6's), and leaving it in there should cause no issues.