High blood pressure could be a side effect of St.John's Wort.
Dizziness is another side effect of this supplement (hypertension is a silent disease, usually without symptoms, but, headaches and feeling dizzy can be symptoms of high blood pressure).
Hot, puffy cheeks could be nothing serious (puffiness due to water retention during menstrual period, and feeling hotter is normal due to hormonal changes).
If you notice additional redness on your cheeks,check for the skin condition known as Rosacea.
Best wishes!
Marija