If you are not ready to seek a prescription, you can purchase similar vitamin A derivatives directly off the shelf:

Visit a primary care doctor or a dermatologist for an in-person skin assessment.

If they determine tretinoin is right for you, they will write a prescription.

Could you tell me a bit more about what you are trying to address (such as acne, wrinkles, or dark spots) so I can help you determine the best strength or recommend a starting routine ?