Pain and swelling next to the thumbnail of the foot is mostly caused by onychomycosis. If the pain, redness, swelling or other symptoms are not obvious that the condition is very light, not particularly serious, can be dealt with through the following aspects: 1, as little as possible to walk on the ground, wear loose shoes, can avoid the nail further stimulation of the tissue next to it. 2, pay attention to the hygiene of the area, do a good job of disinfection of iodine povidone, and if necessary, further trimming of the nails. If the pain is obvious, do not trim too much, because the process of trimming the nails is also a certain stimulation of the surrounding tissue, and will have a certain impact. While most of the milder ones can be relieved by the above two methods, if there is no obvious relief and further aggravation, or even signs of pus, you should take cephalosporin anti-inflammatory drugs orally to prevent further aggravation of the infection. If the condition is particularly serious, surgical treatment may be required.