I have very bad sciatic pain...however lately the pain in my foot has felt very different and much more painful than normal...could it neuropathy?

Unlikely!: It would not be relegated to one foot. It is the progression of nerve root compression which might get worse. You probably will need surgery, but you need a neurosurgical or orthopedic spine specialist's evaluation. This will no doubt included and MRI with a thorough exam. Electrodiagnostic studies by a physical medicine specialist and /or neurologist may be needed as well. Good luck!

I have very bad: If the pain is only in one foot, especially on the side of sciatica , usually occurs from a herniated disc/nerve compression on the same side. Neuropathy usually affects both feet. Best see a neurologist, pain specialist or a neurosurgeon for accurate diagnosis, if pain is becoming so severe, i would see someone soon.

?tarsal tunnel: It would not be unique if your gait has changed to cope with your back pain. This can result in secondary problems in the foot such as heel spurs, plantar fasciitis, tarsal tunnel syndrome, even a neuroma. Get a consult from a podiatrist. An EMG can discern a focal mono-neuropathy.