Does a herniated disk get worse over time?

Not necessarily: If you continue with physical therapy and avoid/limit activities that impact more on the disc it should stabilize and minimize related discomfort/problems.

May, but usually NOT: Epidemiology studies and long term follow up studies have shown that over a 10 year period, disc herniations gets better. The size of the herniation decreases. But saying that what is really important is the nerve root compression and irritation. This to has been shown to improve in the majority of cases with conservative care.