Ingrown toenails are an unpleasant condition in which the nail digs into the skin of the nail fold, this leads to inflammation and can cause infection. The condition can be genetic, and it can also be related to tight or poorly fitting shoes and other similar factors.
I cannot explain why one of your toenails seems to have this occur more than another. However, in addition to wearing loose well fitting shoes there are several things you can do to prevent this. First, make sure to keep your skin clean and dry and use a good antibacterial soap. Also make sure to properly trim your nails straight across. When you first notice some redness or swelling, you can begin to soak the foot and, as you have done, elevate the nail bed.
If this does not work, and if you continue to experience episodes of infection, you may want to see a
podiatrist, as they may be able to cut or file the nail, changing its shape as it grows and preventing future episodes.
As always, if you do have an episode of infection and the area becomes very red and inflamed, you will need to see your
doctor as lancing or oral antibiotics may be necessary.