I can understand the nervousness. Little over a year ago I was in an updraft in the mountains that sent me climbing over 3,000' a minute. That was with the collective as far down as I could with out overspeeding Nr. Even with the turning around I was doing, I still climbed over 5,000' before I got out of it. The thought that was scary was what the downdraft was going to be like on the other side. Really opens your eye's.
It may take you a little time to get back into that type of situations, but I like to think of it as learning yet another lesson. And maybe now seeing that it may not be as wise to go in all the situations that you had previously.
An interesting discussion would be, what speed are you going to use in moderate/severe turbulance. The book does not obviously have a "manuvering speed" like fixed wing, but too fast, a good bump, and you can experiance blade stall. In a 500, I like to keep it somewhere in the 90 kt. area (and slower if at high altitude).