I lost my FA 31 before I had a chance to damage it!
I did ding the metal hood on my Sigma 8-16 and asked here how best to repair it (pliers with cloth etc) and was advised to simply take it to Sigma, which I did. Was US$60ish equivalent to get back a new-looking lens.
I'd email the above picture to Pentax Europe and ask how much.
Seems a shame to have such a beautiful lens scarred like that. Alternatively, you could beat the hell out of your DSLR and other lenses and go for the seen-heavy-action photojournalist look!