For example if we have x=953, I want to select specifically the first digit (or the last two) and save it in another variable, so the outcome would be y=9 (or y=53)
Hydroquinone has also been linked to a medical condition in humans called ochronosis. This condition has actually been found in humans, not rodents, but the evidence is inconclusive at the moment. Ochronosis is a condition where the affected skin darkens in color, and also becomes thicker in texture.
You did not mention what strength hydroquinone you have been using. Prescription strength 4% hydroquinone is better than any OTC product for lightening dark spots in the skin. These dark spots are typically due to chronic sun damage so daily use of sunscreens is essential in your treatment.