Hi. Greetings. Pimples may often leave spots especially if not treated or if we burst pimples or pick them. You'll need skin lightening creams for a specified duration to reduce the marks , and this could also be dealt with chemical peeling. Also you must use a sunscreen to prevent darkening of the spots. For scars, creams may not work n you may need procedures like microneedling, microneedling rf, fractional lasers, prp or subscision or a combination of these. As you mentioned lasers are necessary and depending on type of laser and extent of involvement may range from two to eight thousand per session. Laser treatment it's good for starch marks also. However there may not be hundred percent improvement. Send in your pictures if you need further assistance. Or see a dermatologist near you and discuss the same with him. Hope this helps. Warm regards.