Yes, I think you will receive pain relief with this salve and I would encourage that you apply it liberally since it should not make you high. Topical application of cannabis is rarely absorbed systemically except if you are doing the high THC patch, then you are likely going to experience the psychoactive effects of the THC. You may want to add CBD, either orally or vaporized to reduce any inflammation since that is also what contributes to pain with the herniated disc.
You do not necessarily need to have a herniated disc operated especially if we stop the inflammation, eventually the herniation will calcify. If the herniation interferes with your bladder or bowel control that requires medical valuation immediately.