Ok, so sorry to hear that your eyes are burned by welding flash, which is quite damaging and terrible. Anyway, once got some welding flash into your eyes, you will tend to get watery eyes, painful eyes, as well as photophobia sometimes. The flash would lead to a dramatic drop in your vision for sometime, so you need to take care of it right away. If lucky and treatment is received, it might last about 2 weeks before you are recovered, I recommend breast milk, that is effective when dropping it into your eyes.
It is so bad for you to get the burned eyes by welding flash in an accident. The flash burn from welding may last for about a week. If you treat it well, you may get recovery soon. You could use the cold compress to make the eyes feel comfortable. In addition, you could use the eye drops to release the eyes.
Generally speaking, it is dangerous to have burning eyes after you suffer melting accident. At that moment, your eyes will feel flash burning, and at the same time, painful. In common, it will take two days for this feeling to disappear. Of course, you can just try some ways to treat it. Cold compresses are needed. Also, you can use a thorough rinsing with cold water, so that it will not irritate the eyes. I would suggest that you should not wear contacts, because it will damage eyes and make the eyes infected. By the way, you can use eye drops, which are a very good idea.