Semi-Permanent Hair Colour and Permanent?

Yesterday I used a semi-permanent light brown hair dye on my hair. I have dark brown hair. I left it in too short and it didn't work at all. I really wanted to have light brown hair by tommorow. I bought permanent hair dye instead, but i'm not sure if I should use it over the semi, even though I don't think it worked at all. I don't think it will do anything bad, but my mom is afraid it will, Will it damage my hair if I do so?