My scar has been caused by burn when I was young. So if I stop using minoxidil, will the hair stop growing or fall? (photo)

Is that an under water photo? What is it of?  Despite the photo, if you stop using minoxidil any growth you gained will be lost.  Minoxidil only works as long as you use it.

Hi mercyMinoxidil is FDA approved for genetic hair loss.  It can be used "off label" in other conditions like burns, alopecia areata and scarring hair loss conditions.  When used in burns, the rules are a bit different.  Some hairs will likely be minoxidil dependent meaning once you stop those hair might thin.  But certainly it is not likely to be the same proportion as we see in genetic hair loss. In genetic hair loss, any hair that is gained from using minoxidil is lost. In scars, minoxidil can influence blood supply and remodelling to some degree such that it helps some hairs to grow normally again.... and helps some fragile hairs push their way through scar tissue. When minoxidil is stopped, some of those hairs keep growing. This is particularly evident during the early period after a burn. Be sure to speak to a knowledgable hair loss physician to review all your medical information and to evaluate whether minoxidil is right for you. Hopefully this helps you with your question. 

The photo you sent does not help me understand what is your problem. Minoxidil works to grow hair in 50% of people but the growth varies from good to poor. IF you have good growth and stop the minoxidil, you will lose your minoxidil dependent hair.