The needles used in acupuncture are extremely fine, and insertion of the needle through the skin produces very little sensation. Once the needle is through the outer layer of skin, you might feel a heavy or distending sensation at the acupuncture point. Some people experience a bit of discomfort similar to a mosquito bite. Sometimes this feeling radiates along the corresponding channel, producing sensation that is distal to the point being needled.  It’s not uncommon to still feel the needle after the treatments.