Say we sprain an ankle. Immediately after the sprain, we may not feel anything - no change. Then within 10 minutes a whole cascade reaction occurs: there is sudden swelling, pain, the range of motion is limited, the ankle cannot take full body weight.
The Western approach is to numb the pain and chase away the swelling with ice, then maybe bind it. After several days, the pain is reduced... but the problem doesn't seem to go away: the ankle is still easy to reinjure. People are just told to expect they will have "weak ankles."
This is not a solution.
The swelling is purposeful: it accomplishes two main functions: to bring nutrients and resources to the injury, and to splint the joint, protecting it from being able to move and therefore exacerbate the original injury. Trusting that the swelling has a purpose, the trick is to accomplish what it was trying to do so as to avoid the need to swell up.
An acupuncturist will want to increase circulation to the injured area, not reduce it. In mobilizing the joint as much as possible, there may be pain during treatment, but afterwards there is often dramatic reduction in both pain and swelling...
And the process gives the body and mind a chance to understand the injury. Consciously being careful about use of the joint reduces further injury, reducing the body's need to splint with fluid accumulation... I had a sprain about 7 years ago. I treated with massage and acupuncture. It hardly swelled up, while giving me little pain. I found that if I was careful about good alignment it was hardly a hindrance to me. And I have not since re-sprained the ankle.
The intention is solve the problem, not merely mask symptoms.