It can be subconjunctival hemorrhage
Welcome to health care magic
Iam Dr Dadapeer K, an Ophthalmologist and I answer health problems related to eye.
It seems from the history that you are having red patch in the eye.
Please see whether you have other features like watering, pain,discharge, blurring of vision...
If you do not have any of these symptoms and it is only red patch as mentioned in your question it is because of sub conjunctival hemorrhage. It follows minor injury
or rubbing of eyes. The condition is self limiting and it will resolve by two weeks and no treatment is required.
If symptoms like watering discharge blurring of vision pain are present it can be infection of eyes in the form of conjunctivitis
and requires treatment by antibiotic eye drops.
You can send a photo of the affected eye if you are in confusion so that I can answer more accurately.
Hope I have answered your question and the information is helpful to you.