I was released from hospital yesterday for od on tylenol (acetaminophen) been having severe pain in the head...feels like head going to explode mainly on left side?

Liver & brain: Tylenol (acetaminophen) causes liver damage, and, as a result, may cause swelling of your brain. Because there's no information here about how severe your tylenol (acetaminophen)-related injury is, I recommend you return to the Emergency Department now and / or contact the physician who treated you. This headache may represent a significant issue depending on timing and severity with respect to how tylenol (acetaminophen) affected you.