Well, let me explain you that:
If you had a cyst
underneath the lid, the cyst will not in any way, change after myocardial perfusion scan.
Myocardial perfusion scan is a scan in which a radiotracer (tiny amount) is injected intravenously and that is totally innocuous as far as the same is concerned.
This has a radiation
associated but has never been associated with any other side effect.
Regardless of any of the molecule that is injected, they may produce sometimes rarely mild symptoms like headache or allergic reaction
e.g. itching etc (that too very rare). However, these kind of symptoms disappear in a day or two but the symptoms that you mentioned like pressure behind eyes
, cheek and nose (if the same last more than 48 hours, the same is not due to myocardial perfusion scan).
Therefore, you need to consult your personal physician to rule out other causes responsible for these symptoms.
Let me know if you have further concerns.