Whats wrong with my hitbox?

local dmg = false

DMGPart.Touched:connect(function(Hit)
    if not dmg then
        dmg = true
local human = Hit.Parent:findFirstChild("Humanoid")
        if (human ~= nil) then

   human.Health = human.Health - 15 

 wait(1)
           dmg = false

PunchPart:Destroy()

     end
    end
end)

This damage script rarely works please Improve it.