Thanks for the photos and further detail.
There are few likely reasons;
1) Thick saliva
2) Acid reflux (gastroesophageal reflux disease / GERD).
3) Post nasal drip.
These issues stimulate the accumulation around the uvula. Any of above or any permutation combination of above causes can be responsible for it.
For post nasal drip following measures may be effective;
1) nasal saline spray; do not need prescription for it.
2) nasal corticosteroids / nasal cromolyn / nasal antihistamines may also be needed,
3) oral leukotriene inhibitors and
4) oral antihistamines; like Claritin D which is over the counter.
For problem of thick saliva, following measures would be helpful;
1) Overall body hydration through ingestion of adequate water every day is very helpful measure.
2) Avoid habits, such as smoking, mouth-breathing and intake of caffeine-containing beverages.
3) Avoid medications like chlorpheniramine, doxylamine, dexbrompheniramine, triprolidine, brompheniramine, diphenhydramine, pyrilamine and phenindamine.
4) Drink ginger, chamomile or green tea to stimulate saliva.
5) Celery helps stimulation of saliva glands and adds extra moisture to mouth.
6) Nux Vomica 30 (two globules four times a day) is a good homeopathy remedy for dry mouth.
Following is recommended for the prevention and treatment of acid reflux;
1) antacids; Maalox
2) acid blocker; Prilosec
3) loosing weight, if overweight.
4) avoiding alcohol, citrus fruits and juices, chocolate, and tomato based products
5) avoiding large meals. Eat 5 small meals in a day.
6) wait three hours after the meal before you sleep.
7) elevate head end of the bed by 8 inches.
Following also is advised; Adopting strict oral hygiene regimens, including flossing, careful and thorough brushing, and the use of a periodontal cleansing aid. Frequent dental appointments for topical fluoride applications and pit and fissure sealants.
Please feel free for your follow up questions.
I would be happy to assist you further, if you need any more information.
Thanks for using Just Answer.