Can someone help

I have started getting eczema on my body and dermatitis on my face. I can’t think of really any other new product I have used since developing it which means it must be an old product I am allergic to or something.

Can you develop a reaction to products you were previously using?

Can hay fever or humidity trigger this? Water?

I really need help because I am so sick of this. I just want my face at the very least to stop being dry and flaking skin everywhere !!