Judging from my own experience with acute achilles tendonitis, I would say you can eliminate the pain and discomfort over night, in one day. My left achilles tendon became extremely painful when cycling the pacific coast bicycle route in 1993. It looked like the entire trip would have to be scrapped and I would have to go limping back to Florida. But I decided to combat this infirmity. I decided to try something to cure it, and it worked.
I bought a tube of aspercreme and a small bottle of DMSO (dimethyl sulfoxide). I laid over in a motel in Eureka, California taking the room as early in the day as possible. You have to wash the affected area of skin thoroughly with hot water and soap. Rub in the aspercreme as directed. Give it plenty of time to absorb. Wash that off thoroughly. Apply the DMSO. Let it absorb. I applied and reapplied like that all day long, into the night until I had to sleep. The next morning my extremely painful inflamed tendon was 100% pain free. I was able to continue cycling to San Diego without the least bit of discomfort or pain in that tendon, at all. It works.
There is a caution that comes with the solution. The DMSO must be the highest pharmaceutical grade, 99% to 99.9 percent pure. It does cross the skin barrier and enter the bloodstream. Put it on your foot and later you can taste it in your mouth. It is possible it could transport some kind of microscopic pathogen from the surface of the skin into the bloodstream, like a virus. That is why the skin must be perfectly clean and sanitary before you use it. That is also why some people will not use DMSO. It is perfectly safe to use when used properly. In fact, you can drink a little of it with no harm to your insides. It is sometimes injected directly into the bloodstream, but that is a qualified medical procedure, and I would never do that. Not ever would I recommend that anyone else try doing that.
It works. It completely cured my achilles tendonitis over night. That problem with that tendon has not ever come back. 100% cured, never to reoccur.