I have these dry patches on my legs and i dont know what it is or how to cure it. it just suddenly appeared?

Eczema?: It is tough to tell just from your description exactly what these spots could be due to without a physical exam or picture. However, it is possible your "dry patches" are due to "eczema". This is basically inflammation of the skin cells. You can try an over-the-counter hydrocortisone cream to see if this may help. If not, it would be wise for you have a doctor examine it. Best wishes.

Likely Exzema: try some lotions and fatty soaps. If no help, see your doctor for further help.

POSSIBLE ECZEMA: Dry patches could be due to eczema but sometimes fungal infections and psoriasis can look like eczema . Physician review would help confirm the diagnosis.