A similar thing happened to me once, it was in hidden folder. Have you deleted any folders/apps. What I did was back up all my Data using Desktop Manager (you could back up any Third Party apps using BBSAK) then perform a security wipe on your device. The BB will then return to its default state, then restore your data and any Third Party apps. That's what I did and I got the icon back.
Check out the 'How to' guides here, very informative.