I was sentenced to 150 days in a minimum facility for under the influence of meth. Had 50 days left got a pass to leave and never went back.
The court may very well dismiss any open cases you have and any open violations of probation. But any unserved sentence is going to a bigger problem. What’s working in your favor is that records from 20 years ago in SLO County can be pretty hard to find – they’ve almost certainly not been digitized. I suggest you speak with an attorney who can locate the records to determine where you case is at procedurally – and what your best options are.