I have burn marks all over my leg from a stronger laser. How do I get rid of this? (photo)

It does look like the wrong settings were used and possibly the handpiece didn't have full contact with your skin. You could need a steroid and healing creams and possibly a 4% Hydroquinone,  they key to minimizing the potential for permanent marks is early treatment.  Did you try contacting the office and seeing the technicians supervising physician?  They would typically get you in immediately and started on the right protocol for healing. If you aren't comfortable returning to them I would see a Dermatologist or Plastic Surgeon that is familiar with laser hair removal and performs them as well immediately.  I would at least call the other office so they are aware and can review the settings/treatment protocol with the tech that performed the treatment so this doesn't happen again.  Best of Luck!!

It is obvious from your photos that the skin was not cooled appropriately during your treatment.The settings were probably not appropriate as well.  You should contact your provider or physician to let them know what happened.  At the very least you should be using some type of topical cream to help this heal without complications.

I'm sorry this has happened. I'm not sure if the right laser was used for your skin type. The settings might have been off as well. Also, if the handpiece is not set perpendicular to the skin, the cryogen will not hit the same spot as the laser and you will see scalloping as seen here. You need to maximize your treat to take care of these so the side effects are minimized. I would see a Plastic Surgeon or Dermatology today. You probably need to start on topical or oral steroids, and topical healing creams. 

Hi, I am so sorry for your outcome.  You do have burns from the laser treatment. Burns can happen with laser treatment, but this is quite extensive and unacceptable. Either the cooling tip wasn't working or she did not apply the cooling tip in a uniform manner.  
I would see your local dermatologist ASAP, for proper wound care and to minimize the chance of infection and scarring.  
I would also inquire as to the qualifications of the individual who provided your treatment.   It is always recommended to see a board certified physician (dermatologist/plastic surgeon) who has the training and experience in using high energy devices.  Thank you, Dr. Arora