How to you treat a herniated disc?

Many different ways. We usually combine physical therapy with pain management. You may need an MRI of your spine to look at the slipped disk if you are not getting better. At times a focal pain injection or even surgery is needed to improve the pain.
Depends. If it is early (less than 6 weeks of symptoms), medication, gentle exercise, activity adjustment may be enough. More severe pain may prompt an injection. If it causes serious nerve problems such as inability to empty the bladder or severe weakness, surgery may be the best answer. Most disk herniations get better over 6-12 weeks. Surgery is for more severe problems or failure to improve.
Meds, PT, Time. Most cases will resolve spontaneously, and as long as no alarm symptoms are present (fever, weight loss, anesthesia, severe weakness) can be management by avoiding activities that trigger pain, anti-inflammatory drugs (naproxyn, eg), and stretching or physical therapy. These plus time will resolve the majority of cases.
Depends. If you've done the physical therapy and no relief, then injections like epidural steroid injections or facet joint injections may be the next treatment options. There is growing evidence that stem cell therapies can also be helpful and heal tissues but are not covered by insurance at this time.