Hello Dear SL (my headache "buddy")
You have my complete sympathy, dental pain is the worst thing. I suffered for several years with intermittent abscesses due to a grumbly old root canal treatment. When my original dentist completed it, he said it'll probably last you 10-15 years. Well I made it to 20 or thereabouts. A couple of times a year it would niggle me and each time the dentist would say it was probably going to need extracting but through fear I kept putting it off. I saw a specialist who advised I would probably need an apicoectomy (where they slice the gum open to get to the nerve) but the £600+ price tag put me off at the time because I couldn't afford it, especially when they could not guarantee it would even work and not need extracting anyway.
I ended up having it removed after a really nasty infection and to be honest it was a doddle and a relief to see the blimmin back of it!
One thing they did suggest when I needed pain relief was soluble aspirin (strangely enough it works really well on my headaches as well) and to hold the dissolved solution in my mouth swilling it around the tooth for a bit before swallowing as normal. With an abscess they also said it was likely to throb more if I was laying flat, so the little sleep I got I was propped up a bit in bed. I always felt better cupping my hand round the sore side, so maybe the gentlest of heat? Have you got a microwaveable/wheat pad or anything similar you can just hold against your jaw?
Really hope you start feeling better soon x