When you tell someone that he looks like death warmed over, what you mean is that that the individual looks very tired or ill.
Examples: “when I saw Deepa in the hospital last week she looked like death warmed over.”
You could also say that she looked like death warmed up. The British say `warmed up’, while the Americans say, `warmed over’. It is also possible to say `to feel like death warmed over’.”
Examples: “After going on a twenty mile trek, I felt like death warmed up.”* “When Anuradha came to office this morning, she looked like death warmed over. So my boss told her to take the next couple of days off.”