Advice about submitting a review

I've been divorced for nearly 13 years. I have never had child support reviewed. The amount I recv now is based on my ex making $8 hourly. He now owns his own business and I would estimate makes around $100,000 a year if not more. This is a joint business with his wife. I'm just afraid if I try to have it reviewed he will be able to make it look like he has zero income or that the business is solely hers? I just feel that my child is being shorted and has been for years. I just need some advice on what I should do?