Acupressure and acupuncture are sister techniques. They have the same origin and are based on the same philosophical principles. The only real difference is that acupressure uses hands, fingers and knuckles; acupuncture uses needles.
Dry needling uses a single fine needle to stimulate muscles one at a time. This function is best recognised in modern medicine because it relieves myofascial pain. It seeks an intense physiological response to reduce muscle pain and soreness.