Hopefully you've been dieting for at least that many weeks prior, bro. Can't say specifically because I don't know your stats, but if you expect to look good on stage after dieting for only 4 weeks you've got some disappointment looming on the horizon.
That said, your question is painfully vague. How many calories are you eating now? What is the breakdown of your macros? How much cardio are you doing and how long have you been in a deficit? We gotta get some info if we're gonna help you, man.
Not trying to flame but I've seen plenty of guys step on stage thinking that a month of dieting would be enough and they look soft as sh*t compared to the guys who really did their prep - just don't want you to find yourself in that position.
I'm 10 weeks out and I've been in a deficit for over a month.