Yes, if the layer is rasterized there's not much you can do. Also, make sure the layer is selected when you try to change the text.
And also you need to have that text's font installed in your computer. If not, the program will replace it with another one
If theres a T on the right of the layer, you should be able to edit it. If not, then the layer is rasterized and you cant change it anymore. As Katy said a screenshot would help! EDIT: Looks like the layer is rasterized, meaning its not editable as text anymore, it acts like an image.
There are 2 different types of Text (that's how I like to remember it) Rasterized Text Non-Rasterized Text (Normal Text Tool Text) Rasterizing text makes the writing as if it were a picture. For example, you can't just go inside of a family picture and then start backspacing people out of the photo. Same thing with rasterized layers However, Non-Rasterized Normal Text tool text is text that remains still editable and is treated like words in a Word program. You can't do advanced stuff with it unless you rasterize it, but don't rasterize it unless you save a backup or you are 100% you are final with it.