You can use ice pack or ice massage firstly till numbness , later on use heat bag on the painful area
Also, try to move.

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you can consult a physiotherapist
since the pain radiates to the back of thigh and leg in sciatica a physio modality like IFT will help you in such kind of radiating pain
sciatic nerve stretching will also help you
but since the primary problem lies in the back it also has to be treated
you can go in for for hot water fomentation to the back
also certain back stretches and strengthening exercises have ti be learnt by you
you acn use analgesics if pain is too severe

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Firstly, Prolonged bed rest is not at all recommended unless the pain is very severe, for which it needs to be looked at first. You may use cold or hot packs on the painful areas for upto 20 minutes several times a day to help with relief of the pain. Mild back stretching exercise would help provided that you remain still during the exercise and don't lose balance and/or make sudden changes in movements. Pain killers may be taken to replive the pain and inflammation as advised by your Doctor. Mild ayurvedic massage therapy has also been proven to help in relief. If you can do mild exercise everyday, the body releases natural pain killers and helps to combat chronic pain, but do this only after discussing with your Doctor.