Am I wrong?

DH’s Mom bought me some all natural stuff from a brand she uses. It’s kind of pricey and I would never spend the money on myself. I was waiting to use this jar of salve, till I used up some other stuff I had then I was going to open it. Come to find out she was here for a surgery I had, she took it out of my linen closet and opened and started using it. Didn’t ask if she could use it or not. After she left I couldn’t find it. I texted asked her where it was because I saw her with it last and she’s like “oh I was using it and left it downstairs” (basement guest room). So I’m over here thinking you bought it for me... it was a gift and you didn’t even ask if you could use it. I was saving it to use when I finished some other things I had opened because I wanted to enjoy it. She says that she kept meaning to ask if she could have some but I was sleeping (recovering from surgery) and she forgot.

I think this is extremely rude. Not only did she open it and use it without asking but she took it into her room to continue to use during her stay. I try not to be offended by things but this was ill mannered. DH doesn’t get why I’m upset about it. He says I should bringing it up to her if it is such a big deal. But to what point now that it’s a month later?