How can I fix this patch on my beard? I'm 22 years old. My mustache hasn't connected yet. What can I do please? (Photo)

My dad is having a full beard... I mean Every where is bushy on his face.. My senior brother who turned 24 years recently is having full beard but his mustache is not growing though... Please what can i do to fill in this patch and to turn this vellus hair into terminal? Here are pictures of the patch.. On my right is not too patchy compared to the left... Please i really need to fill in this patch.. I feel really shy going out cause the patch is not looking too good... Help please.. Thanks