How many sessions is usually required for blemish treatment?

Hello. I wasn't particularly concerned about it before, but recently, pigmentation around my cheekbones and cheeks has started to become noticeable, so I am considering a consultation with a dermatologist. I am writing to inquire first to find out if the treatment is a one-time procedure or if multiple sessions are necessary depending on my condition. I am also curious if the number of treatment sessions varies depending on the type and depth of the pigmentation when planning blemish treatment. Please explain how often I typically visit the clinic for blemish treatment, and how much clearer my skin becomes overall with consistent treatment. Additionally, I would like to know what kind of daily care is best to incorporate to prevent pigmentation from reappearing after treatment. I would also like to know if there is a difference between receiving only the procedure and combining it with home care, and if I can receive specific guidance on the expected treatment duration and aftercare methods during the initial consultation.