I had my teeth cleaned last Wed. I have a hx of mitral valve prolapse with regurgitation and did not take the amoxicillan until 3 hours after the appointment. I did not realize that they were about a month exp. That same day, I experienced some chest pain (not the norm for me) and now today I feel achy with a headache and neck pain. I am also doing a liquid only cleanse and the headache feels more like sinuses j; plus I went hiking over the weekend so I am not sure if my sx are coming from that or something else.I I thought about taking another round of Amoxicillan (not expired). My temp is 98.8. Just want to make sure I am not having any early signs of endocarditis.