Need some help installing the retaining ring on my Submariner!

[---rolex---]

Last night I wanted to change the bezel on my 1994 Submariner 14060. I tried to pry it off with a thin knife but ended up removing the entire retaining ring and crystal. I was able to force it back closed with my hands. But this morning I noticed a speck of dust on the inside of the crystal that wasn't there before, and it would drive me mad if I didn't get it out. So I took off the retaining ring again and cleaned the crystal. But now I can't seem to get it back onto the watch, and I've been trying for hours. Do you know of a method for putting it back on without using specific watchmakers' tools? I've heard of using a PVC pipe that's just the right size can work. Any other ideas?

Thanks for helping me undo my stupid mistake!