Hi, happy new year. can hard scrubbing of the skin cause petechiae? and if yes, why does my petechiae keep coming and going, if i've stopped scrubbing

Need to be checked: If you are having petechiae you should get it checked as it is not normal.You need physical exam and confirm that it is petechiae.And may need a blood test for platlet count and other tests to find the cause of your petechiae.

Go to doctor: Petechia are minute ( tiny } hemorrhagic spots, of pinpoint to pinhead size, in the skin, which are not blanched by pressure. (you press the spot it does not turn white). The capillary is hemorrhaging (bleeding )into the skin. You can not scrub them off with hard scubbing of the skin like this toddler. You may have a bleeding disorder.

Yes: But there are multiple issues possible. Platelet dysfunction. Medications-aspirin and others will cause platelet dysfunction. Abnormal lab testing may show cause.