I am getting this warm sensation in on my entire thigh. mainly the left, but some on the right leg too. its warm to the touch but without pain, and is kind of red in color. i have ddd and have a 2 inch synovial cyst. could this be an issue with that?

While sensory symptoms in one or both legs may be caused by a spinal cyst, I wouldn't expect associated skin redness. Cellulitis, a bacterial skin infection requiring systemic antibiotic treatment, causes spreading redness with burning sensation. Because of this I recommend being examined by a physician ASAP to check for presence of cellulitis,and if present,get started on treatment.