Widely spaced teeth and little teeth. Do I need cosmetic dentist?

No. There is no such thing as a "cosmetic dentist". Cosmetic dentistry is not a dental specialty. Any general dentist can perform cosmetic dentistry. Many general dentist take additional courses in cosmetic dentistry but all can perform the procedures you likely need.
Smile. It is amazing what can be done today with petite teeth and spaces. Please discuss with your dentist to hear all your options. He may also refer you to a orthodontist who can close spaces, or a prosthodontist who can make the teeth larger. Also periodontists can make teeth appear larger with gingival sculpturing. Visit websites and look at the gallery of before/after pics.
General dentist. There is not a recognized specialty for cosmetic dentistry. You can pursue care from a general dentist or prosthodontist. Some general dentists have more of an interest in cosmetic dentistry than others. I would ask friends or search online reviews.
Possibly. If widely spaced, little teeth bother you and are effecting your self esteem, by all means go ahead and explore your cosmetic dental options. If you are pleased with your esthetics, than do nothing assuming your in good dental health and function. If either assumption about good dental health or function is incorrect, i would encourage you to explore your options to correct one or both!
Yes. You sound as though you may be a great candidate for lumineers, holistic veneers or traditional veneers.
Quite Possibly. If you want to improve the appearance of your smile, and your teeth are small to begin with, cosmetic dentistry is usually your best bet. However, just to be sure, you should also consider orthodontic treatment. But, that usually doesn't work as well, since moving all your teeth together to eliminate the spaces will also leave you with a narrower smile overall, which may not look as nice.
It is up to you. If there is an esthetic concern and it is affecting your confidence, then see a cosmetic dentist for options to improve your smile.
No. Nobody really needs cosmetic dentistry. But if you want it, make sure you find an experienced artistic dentist.
Prosthodontist. See a specialist called a prosthodontist. They are specially trained in this type of problem. You may require treatment from a few different specialists to achieve the result you want. The prosthodontist will be the captain of your team.
Cosmetic Dentistry. If you truly have a tooth-size discrepency, then you may not be a good candidate for orthodontia. You may still want to consult with an orthodontist though. You would probably be a great candidate for the new so-called no-prep veneers. Check with the dentist's before and after pictures and see if they have written patient testimonials or a patient you can talk to who has had the same procedure.
Not necessarily. What are your goals and what kind of financial investment are you willing to make? A very well trained dentist will be able to provide several options.
Start with your dent. It is better to start with your own dentist.Most of the dentist has now included cosmetic dentistry as part of theor practice.They will refer you to more specific specialists like, orthodontist, perodotist , oral surgeonand so forth.