A blow, bump, or jolt to the head can bruise the brain, stretch its fibers, or cause bleeding. Symptoms range from “I just got my bell rung” to life-threatening emergencies, so knowing what to watch for keeps you safe. Mild injuries (concussions) often cause a brief headache, dizziness, or “seeing stars.” You might feel foggy, slow to answer questions, or nauseated right after the hit. Memory of the event can be hazy, and lights or noise may bother you for hours or days. Sleep can be restless, mood may swing, and concentration on school or work tasks feels harder. Moderate... Learn more