Muscle contusions from seat belts or impact cause deep tenderness and bruising, often resolving with rest, ice

https://telegra.ph/Chiropractor-for-Serious-Injuries-Whiplash-with-ConcussionCo-Management-Tips-07-30

Muscle contusions from seat belts or impact cause deep tenderness and bruising, often resolving with rest, ice, compression, and gradual activity.