try not to use a&d. it tends to fade the tattoo a little. to keep it shiny and the colors vibrant as when u walked out of the shop use aquaphor for the first 3-4 days, then switch to curel intense care or nourishing, healing etc.
I have had two tattoos and I have always been told to use it 5-7 days. It depends on if you have had it exposed to the sun, your suppose to keep it covered too. If it doesn't get better in the next couple of days I would suggest going to the doctor.
First of all you don't absolutely need A&D. All you need for your tattoo to heal is to moisturize it. A good way to keep it moisturized and not be applying ointment every half-hour is to use a good old "Nivea" moisturizing cream twice a day.