Please help!

Posting anon because I feel like a stupid, shitty mom right now.

My SIL gave me an open can of Similac when I was still pregnant that he baby couldn't eat. So it has been open for about 9 months. I have been feeding this to my baby for two weeks now. I'm so nervous about this. He hasn't been sick or running a fever. Does anyone know the risks for this? Or have words of encouragement?

I will be calling his doctor in the morning.