To my knowledge, Botox treatments do not lead to cracked or aged skin.
Your Skin Might be Dry
If the skin is indeed cracked, it would most probably be due to the skin being too dry. In that case, you would want to use facial skincare which contains hyaluronic acid or ceramics to rehydrate and moisturise the skin.
What to Avoid
Avoid acid peels or skincare that contains fruit acids or retinol that would further dry up the skin. If you have had moderately invasive skin treatments, you should take a break from these temporarily and enhance your skincare applications to restore your skin barrier.
Take a Break from Botox
If what you mean is when the skin looks to be too taut or "frozen", you just have to be patient and allow the effects of the Botox to wear off. The effects of botox wear off in 4 months and your facial muscles will restore their movements.
You have to ensure that you are not over-treating your face with too high doses of Botox in the future.