scalp psoriasis & lymph nodes

hi have bad psoriasis on my forehead and all over my scalp (bleeding, flaking etc) and have been treating it with the coal tar shampoo and liquid scalp application prescribed by dermatologist for months (hasn't improved at all). ive noticed within the last few months that the lymph nodes at the back of my neck are quite swollen and hurt a little if I press into them with my fingers. I'm worried about them but unsure if I should see a doctor, what have been other people's experiences with this?