Under
SC WC statutes you are limited to 500 weeks compensation. Only pariplegics, quadriplegics, and brain-damage is compensible for life. I don't know if your headaches and vision problems could be considered brain-damage or not. My personal experience with WC in another state leads me to believe it would be hard to prevail on such a claim. But I'd certainly ask my lawyer.
The headaches and vision problems caused by what sounds like a CSF leak at the contrast injection site sounds more like a possible medical malpractice case. Typically patients are informed and waivers are signed acknowledging such side effects before the procedure. That doesn't mean that you can't sue for damages, but it does raise the bar of proof required to find that it was caused by negligence of the treating practitioner and not just a statistically normal occuring complication common to such treatment. Usually the CSF headaches, vision and hearing problems are temporary though. There might be something here. Again, it doesn't hurt to ask your lawyer.
I'm not a doctor nor a lawyer and the above stuff is pretty far "outside the box" and stretching the limits to some degree. I definitely wouldn't get my hopes up.
If they're offering the balance of the 500 week wage compensation claim up front and lifetime continuation on the medical there's probably no good reason not to take it, unless by taking it a week(or two) at a time you don't have to pay a percentage of the lump sum to your attorney. Right now in your situtation I wouldn't worry about my lawyers cut.
I couldn't find anywhere in the statutes if SC requires vocational rehabilitation, but if it does, but I'd find out and take advantage of such a provision before agreeing to a lump-sum and settling the case. I'd also push to have the mental health treatment covered given the protracted nature of your injury and the constant pain.
Beyond all the misery and the leagl issues though, you're too young to just give up on life, and honestly SS isn't going to provide for a very fulfilling life. Somehow you're going to have to figure out a way to earn a living and do something with your life despite your disability.
Like I said, I'm not a lawyer - just an electrician with a really bad back. Wish there were better news for both of us, but WC reform is needed in almost every state. How an exclusive remedy can only provide for 5 or 10 years of benefits when people's careers are literally ruined is pretty hard to swallow. But all you can do under the current law in most states is educate yourself and find another line of work within your restrictions/capacity. Life's too short to wallow around...