From the Red Cross :
American Red Cross answered
Signs of internal bleeding include:
- Tender, swollen, bruised or hard areas of the body, such as the abdomen
- Rapid, weak pulse
- Skin that feels cool or moist, or looks pale or bluish
- Vomiting blood or coughing up blood
- Excessive thirst
- An injured extremity that is blue or extremely pale
- Altered mental state, such as the person becoming confused, faint, drowsy, or unconscious