-pest or benificial?

[Jenndarlin]

The other day I was moving a GSP Rock which I had noticed one or two of the "small milipede, catepillar" type creatures climbing on the night before. I picked up the rock and felt a little sting but not too bad but then when I pulled my hand out of the tank I could feel something like "stinging nettle" well i looked at my finger and it was COVERED in tiny almost translucent white "nettles". Took me over an hour to pull them all out with tweezers. got a tiny bit of blister but I thought that was probably more swelling from the sting.

Is this charachteristical of the bristleworms or does it sound like something else???

Thanx
Jenn