Removing ink stain is easier when it is fresh. Doing it several days after you got the stain is harder but these tips would still work.
Put a drop of pure lemon extract on the ink stain.
Use cotton buds to rub the stain or use a small brush to remove the ink stain right after putting the lemon extract.
Use soap and water to wash the spot where you are working. (hot water gives better result)
Repeat the same procedure if stain is still there. This time, put more Lemon extract.
Wash it thoroughly with soap and water, then wipe it dry.
Long time stain needs a lot of hard work but you can still remove it using the lemon extract, soap and water.