If the one mentioned above IS swollen, I would replace all of the caps of that brand in the amp, if not ALL of the electrolytics.Just that one photo? I’m not seeing it unless the rubber seal on the bottom of the caps has swelled, causing them to lean at an angle.
The only other one I see might be one of the 2 that are hot-glued together. The left one might be a touch swollen if you look at the + on the aluminum on the top of it.
How old is the amp? Quality modern electrolytic caps will have a useful service life of 20 years in most guitar amp circuits.