ok, the main problem here is that most of your hair probably doesn’t have enough pigment to be treated. reddish hair on blonds is hard to treat. most of it is not affected. i think a lot of what you have left can’t be affected. technically, no, i don’t think a lot of it will grow back, but some will since that area is highly stimulated by hormones and develops hair over time. i would send a message to sslhr on this board and ask if he ever saw a patient a few years after treatment on the beard area and how the regrowth was. i doubt all of it will grow back in, but some will like i said - it will be new hair you develop over time.
meladine is not considered very effective. run a search here on “beard” and also “meladine” using the search function and read others’ experiences.
there is also electrolysis option to even things out. you can read the electrolysis part of the forum for info on that.
how long has it been since your last treatment?