Can neuropathy affect just one limb (e.G-left leg just below knee)?

Yes. Neuropathy can be in just a finger or toe , arm or leg or many places all the same time. It depends on the cause which determines location and extent .
No Neuropathy. It is very unlikely that your condition is neuropathy with it being only in one limb.

Related Questions

Can a person diagnosed with mild crps also have neuropathy pain in the lower extremity (left leg below knee)?

See Pain Specialist. You may be developing a pain syndrome called complex regional pain syndrome. This should be checked out asap so that treatments can be offered to reduce or eliminate this pain. The longer it goes on makes it harder to treat. Also, the pain could be coming from your spine and may need to be evaluated further. I would see a comprehensive pain specialist that can manage everything you need. Read more...