Guttate psoriasis

Hi, I’ve just been diagnosed with guttate psoriasis (I already have plaque psoriasis but has been under control for years). It started as a small red spotty batch on my torso and 7 days later it’s all over my torso, arms and hands and it appears to be still getting worse. I just wanted to know other people’s experience of guttate and when it will stop getting worse? I feel like it’s going to take over my whole body soon and it’s scary. I’ve been prescribed a very potent steroid, and vitamin D ointment. i’ve only been using it for a couple of days, but it doesn’t seem to be helping and the itch is terrible. Just looking for some reassurance that the treatment will work and the spots will eventually at least stop spreading. Thanks