Most medications do not prevent you from donating blood. Common medications such as those used to control blood pressure, birth control pills and over-the-counter medications do not affect your eligibility. If you have recently taken antibiotics, you must have completed the course prior to donating.
Yes, a tooth infection can cause a headache. Also, be aware that certain sinus conditions can mask as tooth problems.
Pain in a tooth suggests tooth decay or gum disease. However, pain may also result when roots are exposed, when people chew too forcefully or grind their teeth (bruxism), or when a tooth is fractured. Sinus congestion can cause similar symptoms of pain in the area of the upper teeth.