Hello, first of all I would advice you to get an OPG X ray done of your son's mouth. Since he is just 8 years old, it is very important to make sure it is not one of his permanent teeth coming out in a wrong position(known as transposition of tooth).
If after the X-ray it gets confirmed that this is an extra tooth, I would advice its removal as it can cause speech problems in your son owing to its location.
If it is one of the permanent tooth that is coming out in a wrong place, then visit an Orthodontist who can get the tooth in it right place through Orthodontic treatment.
You can consult me directly in chat if you want after the OPG, I will guide you so as to what your next step should be.
Next Steps
get an OPG X ray done and rule out the possibility of that tooth being a permanent tooth.