Silica is available as a tissue salt in many health food stores and pharmacies. It is my go to remedy for foreign body in the skin, and helps to expel these quickly and painlessly. That is things like a splinter in the finger, silica fibres from being in long grass, etc. Take the tablets a couple of times a day until the object is out and any redness around the wound has disappeared.
The tissue salt is also very helpful in supporting the health of hair, skin and nails.
Silica is also a good remedy when insect bites have become infected, there is redness and swelling with red lines extending from the bite. Abscesses may respond to this remedy as well as boils and ulcers. It may be useful when the lymph glands become swollen.
Offensive foot sweat has a reputation of being cleared with this remedy.