Hi, did you get any previous such episodes? Any insect bite ? Any associated pain ? Any disease like TB or Arthritis ?? These answers are crucial to come to a specific diagnosis. The picture isn't very clear but shows a nodule or swelling at limbus i.e  black eye part margin pointing probably to episcleritis like picture. But without answers to above questions i will not be able to give you any specific eye drop.

Hello, any other associated symptoms along with redness? Itching, eye discharge ,etc ? Is it first episode or any recurrence previously? It has to evaluated further