I am writing a book. What are the physical signs of suffocation by pillow after ones death. I know that particulates can be found in the nose and mouth.. But is there anything else? Do eyes bulge, lips turn a funny color? Please help!

Here is one reference on suffocation symptoms:
Symptoms of Suffocation - WrongDiagnosis.com
I have absolutely no expertise in this area except for watching Law and Order.lol
I am just guessing but if a pillow is forcefully pressed against the face, maybe there is some bruising of the face and neck and the bad guy might have his knee or knees on the victim's chest causing some more bruising. There could also be some aspiration into the lungs (maybe). I'm already in over my head and neck. I suggest you check goog.