The 38-year-old career has faltered since losing his WBC light-welterweight title to Tim Bradley four years ago.
Witter is eager to get things back on track, however, he knows anything but a win against Lynes in Sheffield on May 12 will be his final bout.
The Bradford-born fighter beat Lynes on points in 2005 and he is hoping another win over the 34-year-old will be the springboard to bigger and better things.
"This is it," Witter said in the Telegraph and Argus. "Realistically it's the last chance for us both.
"If he wins, he keeps the belt outright and it's a dream belt to win. I've always been the most avoided man in Britain and this is my way back out there. With that intensity brings the fire.
"I'm nervous about this for different reasons.
"I've got to step up, win that Lonsdale belt and then move on and start making big money again. There are opportunities out there like the European that I know I can win.
"I need that exposure but all this depends on me delivering what I know I can do this time."