I think my husband is self harming again...

My husband quit self harming a year and he's been doing so well but recently he's been off. He leaves and will be out all night. I look on life360 and he will be sitting at the park. He is also vaping again. He wears baggy clothes and won't let me see his body anymore and changes in the bathroom. I also woke up to him crying in the bed... He keeps saying he's fine and nothing is wrong. Today I needed the box cutter to open a package. We have a really cheap one but when I went to get it the blade is missing from it... I'm worried he's self harming again.... I told his sister that in worried and she told me to wait until he's taking a shower or something and go into the bathroom and see if he has any cuts on him. I feel like he will feel violated if I do that. Advice plz.