If you are going back to ask for a higher figure, there's no point. If they weren't willing to negotiate before, they won't be now.
If you're going back with your tail between your legs, think carefully about how badly you need the job. If it's a matter of keeping a roof over your head, then give it a shot. However, chances are that the company won't be keen. They will naturally question your priorities and interest in the job itself and, depending how the hire is being handled, you could find yourself tarred by your boss and colleagues throughout your time with the firm.