Do symptoms of sciatica indicate nerve damage and what are more severe symptoms of this?

No: Most times there is no clinical evidence of nerve damage. Pain is typically the presenting symptom and can be variable in presentation as can be numbness , tingling and weakness as well as rare bowel and bladder dysfunction in 1% and that is the most worrisome or severe one.

Not necessarily: Sciatica is a common term to describe pain that travels into the leg(s). This is likely not do to nerve damage but compression or irritation of nerves coming from tha back. Severe nerve damage can result in muscle weakness. Pain does not mean damage.

Not Really: Its hard to tell nerve damage without more extensive testing. Mri, emg/ncs or even biopsy may be needed to assess nerve damage. As a rule of thumb, weakness is sign of nerve damage. Sensory pain can be nerve damage, however its harder to quantify without objective data/findings.