If they’re from your own rose garden and haven’t been exposed to all kinds of chemicals, you can make them into lots of bath/body products (e.g. rose water) or even eat them (e.g. a decoration on cake or desserts). But if they’re store-bought roses they’re likely laden with chemicals & pesticides, so I wouldn’t use them on my body or consume them.
You could still make them into home decorations or potpourri, pressed flowers.
Lots of ideas online for used.