Does medication for fish change ph lvl's?

I was wondering if medication changes a ph lvl of a 10gal tank. I bought some of those hanging ph lvl reader and put it in the tank...then stupidly put in some "BETTAFIX" to heal damage skin and fins some 5min later. I completely forgot about waiting 30min for the thing to read properly and after i came out from the shower i saw the thing and it was marking 8.2(or higher) ph lvl. i did a 40% water change but the ph lvl staid the same. i also use those fizzy tablets to balance the water and it didn't work... dont know what to do now >.< .... any suggestions?(could it also be the water that i use?)...