You were in a car accident, so it’s hardly surprising that you have a few bruises. They’re no reason to worry, right? It depends. Bruises indicate that blood is pooling in the tissues under your skin, and they’re a common response to trauma. Most of the time, bruises look worse than they feel, and they tend to clear up quickly.

However, not every bruise is benign. Bruising around your abdomen following a car accident, for example, can be the most visible symptom of dangerous — potentially fatal — internal injuries. Called “seat belt syndrome,” these injuries can take a while to develop and may initially be painless.

Bruises can also be the sign of a hidden break in one of your bones. If the bruising appears around your cheek, jaw or collarbones, for example, you may have fractures in those delicate bones that weren’t immediately apparent. Only an x-ray can tell for certain if you’re seriously injured.

It’s not uncommon for people to develop blood clots, too, due to damage to the blood vessels caused by traumatic bruising. Clotting agents in your blood can sometimes go awry. While many clots are superficial, any that form deep in your veins can become intensely painful and put your life at risk. You should be particularly concerned about pain in your legs following an accident, just in case you’re developing a clot.

Don’t assume that bruising following a car accident is nothing to be concerned about. It’s always safer to have your symptoms evaluated by a physician as soon as possible. You can hold the at-fault driver liable for your losses, including any bills you have for accident-related medical care.