What Causes Blisters At The Back Of Throat?

Am 46yrs old lady, Working in UAE since last 15 years as an Art Director in a Government Organization. Last couple of months I had pain in my throat, even i was coughing a lot (dry cough) especially at night when i liedown, when i consulted an ENT specialist (in UAE), he said due to acidity there are small granule in my throat . He checked the throat and prescribed medicines for a month - dompy and gasec ( acid reflux) , and advised me to do biopsy if no relief. Now i don t have any pain in my throat, but still i consulted him after a month as per his advice, then he checked the small kind of boil still there go for biopsy for safer side, since am not having any type of pain i have not gone till now. But today i felt something is stuck in my throat - like sand - i thought due to whether change- sandstorm - i felt like that, then i touched by finger in the throat and checked - i felt small 2 boils there - i am not feeling any kind of pain but its disturbs me and moreover am worried as my family history - younger sister died due to ovarian cancer and mom died due to colon cancer. Since my siblings are settled in India - Delhi and Faridabad - I consulted at Faridabad - Asian Hospital - the dr advised before doing Biopsy need to check MRI. Crossing my fingers and praying God not to put me in that list. Waiting for your early response.