How to not damage the same player twice ?

Hi, i've made a script that creates a blast in front of the player. When the ball appears and grows, it's supposed to deal damage to people (or entities) it encounters. I used the ":Touched()" function so it detects every part that touch the blast and it deals damage to its owner. However, as it detects many parts from the same player, it damages the same player more than once. Here's the script :

local transparency = 0
local blast = Instance.new("Part", game.Workspace)
blast.Shape = "Ball"
blast.CanCollide = false
blast.Anchored = true
blast.Size = Vector3.new(0.5,0.5,0.5)

blast.Touched:connect(function(hit)
    for _, char in pairs(game.Workspace:GetChildren()) do
        if char:FindFirstChild("Humanoid") then
            if hit.Parent == char or hit.Parent.Parent == char then
                if hit.Parent.Name ~= player.Name and hit.Parent.Parent.Name ~= player.Name then
                    char.Humanoid:TakeDamage(50)
                end
            end
        end
    end
end)


for i=1,14 do
    transparency = transparency + 0.072
    blast.Transparency = transparency
    blast.Size = blast.Size + Vector3.new(1.5,1.5,1.5)
    wait()
end