Have a read of this
and if you are finding that codeine based pain killers don't work for you, it could be down to a lack of the enzyme needed to make that work, and you have to discuss with your GP using non-codeine based painkillers instead.
Better to find a pain killer that works than over do the heat packs and cause damage to your skin capilliaries.
Erythemia Ab Igne is a skin condition where use of heat has cooked the capilliaries under the skin causing mottled patterns to appear and these take YEARS to recover from.
Lots of us have landed up with EAI through sitting too close to a fire, using hotties or hotwater bottles or having laptops on thighs etc.
If the skin gets cracked and sore then you must stop and get it checked by the GP. This is just as dangerous as sunburn and can lead to skin cancers in the future so please be very careful with applying heat. I know it is so tempting because it does provide relief from pain, been there done that myself, but the truth is occasional use of heat is fine, but with endo or gynae pains we tend to need to use it throughout the day, and day after day and this leads to a significant chance that damage under the skin will be the result.
Use the search box on the green bar and look up Erythemia Ab Igne...we have discussed it a number of times, because a lot of us have ended up with it, not having a clue that the consequences could be a lot worse than temporary pain relief.
I would definitely recommend the op, having it without anaesthetic is crazy and I doubt any surgeon would agree to that and it is pointless as it would far far more traumatic... and you'd probably pass out anyway from the shock, so much better to drift gently in to deep sleep and before you know it someone is calling your name to wake you up.
The op itself is the simplest of things to get through - you are just sleeping and know nothing about what's going on down below which is just as well.
After the op, you get 2-3 days of shoulder pains (due to trapped gas) which you have to fart and burp out of you as quick as you can and once that is gone, you are left with slight soreness of the lap holes and if they did any work inside then tenderness from that for a week or two and pain relief will help but isn't always necessary after the initial trapped gas pain has subsided.
Meanwhile your current pain situation could be resolved which will have you feeling so much better. It is definitely worth getting the op to see what's happening inside.
Be brave. you can do this, as thousands and thousands of us have been through it. It's not nearly as bad as you are imagining it to be. The pains won't be as severe as what you are experiencing now, so if you can get through the current situation without pain relief my goodness you can get through the op, and do speak to Doc about the non-codeine based meds, because a lot of people cannot benefit from those drugs because they genetically lack the enzymes needed to make them work.
p.s. You can take a teddy bear in to the operation prep room with you, and you can wear your own brightly coloured socks to cheer you up too. And do tell the nursing staff of you concerns, most people have them before their 1st op. Once that is over and done with, you are much better prepared for any subsequent ops you may need to have later in life.