Sun Protection and Phototherapy Treatment

hi, would love.to hear if anyone can offer some advice. I am two weeks into my phototherapy treatment, so being super careful in the sun. today I have used spf50 foundation plus spf50 sunscreen....and my face has still burnt. I also wore a wide brim hat. Other thank not going out at all....I'm not sure what to do....I wasn't even sitting out in it! Does anyone have any advice please, recommendations of creams etc... Thanks so much Karen 😊