I'm so upset right now. My son came home from his dad's and he was crying a lot out of no where and…

I'm so upset right now. My son came home from his dad's and he was crying a lot out of no where and he's not like that and I figured he was just tired. I tried getting him down numerous times and he slept maybe an hour each time. I had him laying with me and he was up and all over. So I got up gave him gripe water thinking maybe it's his tummy. Made him a small bottle with some chamomile tea mixed in and then I was like let me check out his mouth which he doesn't really let me look in there so I got a finger in there and he's cutting a tooth a got a peek and it's all red poor little honey so I gave him some pain medicine and hopefully he'll settle down now. :/ I feel awful and his dad lies and doesn't tell me shit. Like this poor baby had to of been miserable and not sleeping for him too and he lies about it! So then I'm left in the dark. Fucking bastard 😠 I feel like telling him right off!