Ink is a dye. It stains the leather and will be absorbed very quickly.
Any product that will dissolve the ink will also dissolve the color from your leather. If the ink is fresh The Leather Solution may sometimes remove it before the leather can absorb it. Home remedies can sometimes work but usually they cause more problems and enlarge the original problem. Small marks can disappear without any treatment as the leather takes them in. Large stains, scribbles can be removed professionally and the area recolored to match.