If you are arrested for DUI, there can be a DMV penalty of a license suspension regardless of whether there is a DUI conviction in criminal court.
If you were convicted of a misdemeanor or felony and subsequently missed a court date, you are likely facing bench warrant and probation violation issues
A DUI can be charged as a misdemeanor or a felony depending on circumstances. For example, a fourth DUI are a DUI causing serious Injury can be felonies. Many DUI convictions can be withdrawn and subsequently dismissed as well.