Lash extensions should feel like your natural lashes, you should not be able to feel them at all. If the process of having them put on, or if they itch, irritate or are painful after application, your lash artist is applying them incorrectly. The experience should be relaxing. Eyelash extensions should feel like your own natural lashes. If the extensions are applied correctly they should not be painful, itchy, clumpy or heavy.
You should not really notice them except for the way they enhance your features. When you first have them applied, however, you may feel them a bit since your lashes are fuller, but the sensation should subside almost immediately. Some people have said that they can “see” them, but this will also subside. At Sylvia’s spa, she uses high quality relatively fume-free adhesive, which should not burn or sting, unlike cheaper inferior products. People with sensitive eyes or sinus problems may get some watering or slight stinging at the end, but it normally subsides quickly.