Had sore throat on right side for 6 days w/o cold symptoms. Rapid strep & culture were negative. I have a large white spot on right tonsil and my throat is very red and irritated. What else can I do?

Depends. While many sore throats are viral in origin, a negative strep test does not rule out other bacterial species which can cause tonsillitis. If your symptoms have been persisting or worsening over the 6 days, the suspicion that this is acute tonsillitis is far greater and would respond well to antibiotics.
Symptomatic care. Most sore throat are viral in origin. If the strep throat is negative too, you would need lots of symptomatic care. Take lots of fluids to drink and tylenol (acetaminophen) for pain. But again you will have to give it some time to get better. One final thing - if your throat is coated with whitish exudate and you throat still hurts by 7-10 days and you are feeling tired, it might prudent to check for mono.