There are several possibilities here, but I think the most important thing is to figure out if there is an association between your headaches and the Accutane. Rarely, taking Accutane can result in a serious neurological condition called pseudotumor cerebri, which require immediate evaluation and treatment. I would suggest seeing your dermatologist
or primary care doctor
immediately to discuss these alarming symptoms and determine if anything needs to be done.
Secondly, dry skin in those who are taking Accutane is extremely common, since the beneficial effect of Accutane come in fact from producing turnover of skin cells, which leads to the dryness. Using a good moisturizer is very important, but if this is not working then you need to talk to your dermatologist to figure out what skin treatment regimen they would recommend for your case.
Of course it is very possible that the symptoms you are experiencing are unrelated to Accutane, and may instead just be related to stress of school and disruption of your sleep and exercise schedule. Skin dryness in common in spring and winter months.
However, before investigating these common possibilities, it is important to make sure that you are not experiencing difficulties related to your Accutane prescription.