If the poinsettia plant came in a foil wrapper, check for water at the bottom before you add more moisture to the plant. Poinsettias are accustomed to soil that’s on the dry side. If their roots sit in water day after day, the roots will rot. Check for drafts in the place you choose to display your poinsettia. Hot air from a furnace or cold air from a drafty window can make leaves dry faster than normal.
After weeks of indoor weather, poinsettias are usually on their last legs and hardly worth saving. If you want to keep them, put the plants in a sunny window and water whenever the leaves wilt slightly. Give the plants some indoor houseplant fertilizer (at half strength) in early January, repeating every four weeks until April. The poinsettia can be put outside in a semi-shaded location then. You can move it to a larger pot or plant it in a flower bed. If it is fertilized, it will grow prolifically, perhaps four feet tall by September. The plant will need cutting back at least twice in the summer to keep it small enough to bring back inside next fall. In my opinion, it is too much trouble go through the gyrations needed to once again achieve the brilliant coloration on the plant that attracted you in the first place.