Hello Sir..A picture would have helped.. according to given history it seems to Subconjunctival Haemorrhage which can occur because of rubbing of the eye.. usually it takes around 10 days to fade  away..if there is no other issues like watering, sticky discharge from the eye or if the baby is not rubbing his eye a lot then nothing to worry about. To be on safe side if you want you can opt for online consultation where we can have a video call for better understanding of the issue and proper treatment if required.