Any damage to, or problems with, the teeth and gums should be notified to a dentist as soon as possible in order to prevent a minor issue turning into a major problem.
A cracked, chipped or otherwise damaged tooth will not cure itself and the problem could worsen considerably if bacteria is allowed to invade the inside of the tooth and adversely affect the pulp and nerves.
Depending on the cause and the extent of any damage the dentist has a number of treatments available:
Delaying a visit to the dentist invariably leads to more intense treatment than should be necessary and also increases the chances that your damaged tooth will turn black and possibly require an extraction.
Following any dental treatment, it may take some time for the tooth to return to its natural colour but this is quite normal and you can find out more at https://yourdentalhealthresource.com/how-to-prevent-a-damaged-tooth-from-turning-black/.