Tìm hiểu nguyên nhân. Để ý dấu hiệu viêm nhiễm. Cảm nhận sức ép. Lưu ý sự xuất hiện của khối u.

Given the above summary, write a detailed text in English for it.
If you are badly bruised or have many bruises but you didn't fall or injure yourself, you should call your doctor. That can be an indication of a more serious problem. It could mean you have a problem with blood clotting or another blood disease. If the bruise doesn't improve after two weeks, reach out to your doctor. One sign of infection is red streaking, where fingers of redness on the skin jut out away from the bruised area. Another symptom is if the bruise is draining something other than blood, such as pus. Also, check to see if you have a fever, as that can be an indicator as well. Call your doctor if you have these symptoms. Other signs of infection are if the bruised area gets more swollen, painful, or warm If you feel a great deal of pressure where you are bruised, that is also a reason to call your doctor. It can be a sign of compartment syndrome, a serious condition that slows down circulation in that area. The area may feel very firm or hard and be very painful. See your doctor immediately if the area below the bruise is numb, cold, very pale, or blue. If a lump forms over the bruise, called a hematoma, that is also a cause for concern. Hematomas are very similar to bruises. That is, they form when blood escapes from a blood vessel. However, they create larger bumps and can be more dangerous.