Weakness can be due to severe pain from muscle or bone movement. The nerves connecting to the muscles, however, also could be injured. If the nerves are pinched, bruised, or cut, you may not be able to feel things normally. A cool arm or hand suggests that the arteries, veins, or both have been injured or blocked. This may mean that not enough blood is getting into the arm.
Redness can indicate infection or inflammation.
Rashes may be noted as well. Bruising may be evident. Muscle spasms or tightness may simulate actual swelling. Dislocation or deformity may cause a swollen appearance or paradoxically a sunken area. May be present if you have a fracture or a dislocation.