It sure looks like the surround is not attached properly to the cone. Have you tried to see if you can move it with your finger. If you can then it has likely come detached during use and you can buy some speaker glue from parts express or modeling glue for gluing rubber tires to metal rims from a hobby shop that sells RC cars/trucks and glue it back down.
If it is still attached just to the wrong place then messing with it will likely do much more harm than good. As suggested above try a blind listening test and I doubt there will be any noticeable audible difference. I Doubt if you could even measure any difference outside an anechoic chamber
