My tripawd Astrid has been missing her front leg since she was 6 months old, and I noticed last week that she was walking with a slight limp. We took her to the vet and they said she has osteoarthritis in both legs, most notably on her left side. They gave us some pain meds (don't have them with me so I'm not sure the brand) and said to follow up in a week. I am nearing her followup, and she has shown no improvement despite applying heat, letting her rest and giving her a pain reliever. 

They said we could look at hydrotherapy or acupuncture and I've seen in other threads that both can do wonders, however I know she is in pain despite no whining and for the most part acting happy. I'm concerned for her, but I want her to go back on walks and be able to go upstairs without worrying about her hurting herself further.

I also noticed two days ago that she is eating much slower than normal and chewing her food when she normally just inhales it as fast as possible. I do not know if this is related or something else and I will bring it up to the vet, I just worry that she will be in pain for the next 4+ years of her life and I don't want that at all.

I also live in the UK now if that makes a difference. 

Honestly I just want some advice on what to ask the doctor or medicine I should know about as this is all a new problem set that I am not familiar with, and in looking online there is so much jargon or medicine that I am becoming increasingly overwhelmed and panicking when I know I shouldn't...