The description you have given is suggestive of a corneal infection very common in contact lens wearers. The location of the lesion, central or peripheral, on the cornea is also important. Causative organisms range from bacteria to fungi, viruses and acanthamoeba and may arise from external sources, unsterile contact lens cases and ,quite often, unsterile or outdated contact lens solutions. Often, the lesion is what is known as a sterile infiltrate and less damaging than an infective lesion but for treatment purposes it is ALWAYS considered as infective till proven otherwise because of the damaging effects if taken lightly. You have to start a combination of an aminoglycoside eye drop like Tobramycin and a fluoroquinolone like ciprofloxacin each to be used every hour keeping a 2 minute interval between each medication. However, your eye has to be evaluated to assess the exact cause of the keratitis and a corneal scraping should be done if deemed required. This gives the organism responsible. If it turns out to be a sterile infiltrate which typically manifests as less symptomatic with almost no pain and redness , then a different line of treatment is followed where mild steroids are used. However this is done only after infection is ruled out. Start the medication but have your eye evaluated as early as possible and stay away from contact lenses till then.