slightly OT - plungers??

Guess if it was the Midget, this would be on topic, but
t'aint.  I got a small, shallow dent in one of t'other cars.
I have eased a good bit of it out with an old plunger, but
now the cup kinda curls and breaks suction when I pull.

I'm really wondering -- is there a PROFESSIONAL
body-shop plunger available? (Looked in a nearby
Advance Auto today and could not find one.) What do
y'all use? Or maybe I should just replace my tired old plunger??

thanks,

chuck