Of course you can bring up the issue, the other person probably got a pay rise because they brought up the issue of pay. It is a case of you justifying why you deserve to be paid more such as increased productivity or the dip in business that triggered the pay cuts has been reversed. There is always the possibility that management have assessed that the other person 'deserves' to be paid at least 20% more based on skills, efficiency, flexibility, sales etc.
Are there defined pay scales in your role? What was the basis for the 30% pay cut and was there an agreement on what would have to happen for it to be reinstated?