Well, I guess speaking as a minority, I'd sue their asses off.
CO has shown over the last few years that nice letters and complaints asking for reasonable mileage/upgrade based compensation are useless. Forget trying to gain a FF benefit from them for this unfortunate incident.
Find a lawyer who will work on contingency, have photographs taken of your scratched tounge, fly another airline from now on, and let the lawyer get whatever he can. $1,000...$10,000...more....whatever, it's found money. Just get it started and don't think about it any more - let the lawyer deal with it.
CO would not think twice about ignoring your complaint and/or sending you a form letter. Threatening legal action makes no difference. Just do it. I assure you, the lawyer will get something and so will you.