I did some experiments with the pain management techniques when I was young, and maybe I can help you a little. Normally I do not share this as we tend to misuse then and end up in hospital or dying, as I almost did ignoring a toothache long enough to get really bad and in need of drastic treatments, but I believe this is not the case.

While mild techniques like visualisation of a nice place or a great memory to create natural endorphines to combat pain may not work at this state, there is a technique that may help, with a bit of practice. It requires a bit of perception switch, and the theory is that we associate good or bad feelings with pain. Most people associate bad with pain, but there are a small percentage of people that associate pleasure with pain (masochists). Which implies that our response to pain is a learned one, and can be unlearned. Once you cut the feeling association with pain, and you see it as what it is, a warning system that tell you that something is wrong in your body, and that this is only an electrical response from the brain, then you can dissociate the feel from the pain. It is a bit complicated, but it is working perfectly if you master it, making you more or less immune to the pain response, while you acknowledge it, but it is not creating a negative response. Some people master this faster than others, but in all the cases, you can decrease the pain intensity, maybe even to the level where it is on the background, but only as a mild annoyance.

Hope it helps. Ask me if you need to know more about it.