Could you explain what is a good way to get rid of severe dry skin?

Moisturize! The major problem is in getting moisture back into the outer layers of the skin and keeping it there. Applying a moisturizer after washing (with a gentle soap) will help do this. And you may have to do this several times per day as is practical. Keeping ahead of the dryness will be a major effort at first but this can get better. See a dermatologist if you need additional guidance.