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.
We see then that dental headaches originate from an unstable bite which cause the muscles of the jaw, head, and neck to overwork and become painful. Once the muscles become painful, a vicious cycle begins. The pain makes you feel tense and uptight. This worsens the muscle spasm, which in turn increases the pain.