Vardenafil/ BlewChew Experience

I was prescribed vardenafil from bluechew (8mg). I decided to take half the dose, for my first time, to see how/if I would respond or if I would have side effects because I’ve never been on Ed meds before. I noticed that my face became red and felt hot, I know facial flushing is a side effect. However, I did not notice any differences with my erection; I realize that only taking half the dose might be the reason, but the facial flushing was pretty intense and uncomfortable that I had to wait for it to subside some before I was even in the mood. I was wondering if I should try another half dose (4mg), take the full dose(8mg) , or not take it any longer? Any info is appreciated.