An abscess is a sore on the gum that is caused by an infection. The only way to treat an abscess is to get an antibiotic from your dentist.
Call the vet. The horse will no doubt need antibiotics and the neck is a bad place to get an abcess.
yes
Yes
Yes
Yes, it can even kill you.
yes but with medical treatment by a dentist
Yes, abcessed tooth cause heart problem.
Delerium, Death, loss of motor or neurological function such as speech !!
Worst case an abcessed tooth... which is horrifyingly painful.
Yes, but you should see a doctor to have the cause of the infection removed and not just take some cephalexin you may have left over from something else! You should be treated for 7-14 days for this to work properly.
Sounds like an abcessed tooth. You should go to a dentist and have it checked.
Your gums bright red too? It's probably abcessed. See a dentist immediately!