More importantly, prevention is better than cure, ie get a auto dimming mask, be odd to start with as you keep shutting your eyes, but work perfect, get one with adjustable shade.
Never really done anything when I have had it, despite not getting it from myself, it's hard to stop flashes when there are loads of people al welding on same bit of metal, structure etc, so auto dimming mask and decent hat, as pissed off with getting burnt on my bald spot.
tabetha