Ingrown eyelashes, while merely annoying at first, could actually be a sign of something more serious. Trichiasis, for example, is a condition where the eyelashes are ingrown as a result of a physical disorder or a trauma; this condition can be painful in addition to obscuring your vision. So while a single ingrown eyelash might be easily removed or prevented, you should contact your doctor to get his opinion if you continue to suffer from ingrown eyelashes.
Rinse your eyelid carefully. Use warm water to ensure your pores open. An ingrown hair occurs when a hair begins to curl back on itself within the follicle rather than growing out through the skin. This creates a protein plug that blocks the pore, leading to inflammation and swelling. By rinsing the area with warm water, it could help move the blockage outward toward the surface.
Put gentle pressure on the blockage with your fingers, much like you'd do if you were squeezing a pimple. Since this blockage is in the delicate area of your eyelid, don't pull the lid away from the eye or apply more than gentle pressure on it. If the blockage doesn't release, proceed to Step 3.
Consult your doctor. Sometimes ingrown eyelashes may go away on their own, but if the infection becomes severe enough, it could lead to further medical problems. The doctor should be able to come up with a treatment that will remove the blockage and allow the eyelash to grow normally again. Or, if it turns out you have trichiasis, the doctor can prescribe a treatment plan for that as well.
Be careful when attempting to remove an ingrown eyelash yourself. The eye is a sensitive area---any unnecessary risks should be avoided. Do not, under any circumstances, use normal ingrown-hair treatments for other parts of the body on ingrown eyelashes. The chemical treatments will damage your eyes, and a needle could easily pass through the eyelid and into the eye.