Some guys even have two different shaped biceps due to genetics. If they don't stress about it, you shouldn't.
Out of curiosity, what's your height, weight, and general bodyfat level?
You're almost definitely seeing a "problem" that isn't really there, unless your wrist injury also resulted in a torn bicep (which there'd be no confusion about. That's a big deal and not something you'd not-notice). Biceps "gap" can change based on the supination/pronation of hand when you flex: