There ingrown toenails and then there are ingrown toenails with soft tissue infection. If there is soft tissue infection a personal visit to an M.D. or a Podiatrist is mandatory. Soaking the toe in hot water is contraindicated unless directed by a physician. Under certain circumstances, if being treated by antibiotics a wet-dry protocol is favored, but that has fallen out of favor by those involved in wound management. Soft tissue infections must be treated by oral antibiotics. The danger is spread of the infection to the bone, which will require debridement and toe amputation. Soaking the toe increases this probability. The problem is especially acute in the elderly and those with diabetes. Toe infections should never be self-treated.
i get ingrown toenails all the time, I have found that the best thing to do is soak it in hot water and take something like a toothpick and try to separate skin from nail.
If you read the book "The Body Electric" by the late Dr. Robert O. Becker you will find the Veteran's Administration, for whom he worked, developed a treatment in 1975 for osteomyelitis using silver foil connected to a small battery causing migrations of the silver ions into the toe and bone. They performed a number of clinical trials, however the technique has been lost and forgotten. At the very least an X-ray film is required to determine if there is osteomyelitis. Often the x-ray will be clear but osteomyelitis will show on an MRI. Protocols change and the current drill is to keep the infectious area dry, as I mentioned..External bactricidal ointments are ineffectual.
I might add that keeping the toe DRY is essential. Soaking in hot water is contraindicated.
Let me disagree as to whether or not this is very serious. You have an infection that is beyond the ability of soaking to cure. If the infection goes into the bone the situation may only be resolved by amputation. There is a problem with antibiotics because oral antibiotics do not reach high enough concentrations in the toe. Treatment is usually intravenously administered vacomyacin, although the Journal of Infectious diseases January 2011 suggests oral Cipro as an alternative. If osteomyelitis of the bone in the toe progresses to the metatarsals it can mean foot amputation. You need an IMMEDIATE consult with a podiatrist.
Simply bath your foot in warm water for ten minutes a few times a day. This is not very serious but it may need an oral antibiotic to clear it. Ultimately you may need to have that toenail removed under local anesthetic. Make sure in the meantime that your footwear and socks are loose fitting and not impinging on that toe.
Time to bring in a local medical doctor to help you imo.