Thank you for your query. An injury to the eye resulting in pain for more than a couple of hours needs to be looked at by a doctor. The injury needs to evaluated for any corneal abrasions or puncture wounds. It may need irrigation to clean the eye of any lodged particles. In this scenario, an injury from finger nail (probably not so clean, since they were playing), associated with redness, swelling and pain (moderate to severe) could mean a corneal injury. If not treated appropriately, it will lead to scarring and other complications. Mild pain, redness that goes away in a couple of hours is OK. Anything more or if the eye symptoms worsen, I recommend you see his doctor right away, which may decide to refer him/her to an ophthalmologist, if necessary. In the meantime, wash the eye with clean boiled and cooled water. Pat dry (do not rub the eye).do not apply any OTC or prescription medications without consulting his doctor (can do more harm than good). Apply cool wash cloth to eye (not cold and no pressure). Do not attempt to remove any particle from his eye (especially with instruments). Anything superficial can be washed off with water. Gatifloxacin (gatilox) is a brand spectrum antibiotics that is used to treat certain types of bacterial infection. This is not indicated for your child at this point. Hope this helps. Please get back to us for further clarification, if you need to. Wish you both good health.