I have what look to be a blister i n right corner of bottom lip. also my tongue gets sore if i eat any thing spicy, salty, tarty . dryness of mouth.?

Two possibilities: This could be cold sore (herpes) or canker sore. Need to know if you frequently get these if exposed to sunburn, etc wh/ is herpes. Cankers more common w/spicy, salty food often preceded by trauma. Frequent canker sores can be prevented with Colchicine wh/ is used to treat gout. Colchicine has a tremendous preventive effect against aphthous ulcers (canker sores).

Does sound like it: Dry mouth can cause what you describe. The lip corner is call 'angular cheilosis'. Multiple medication can cause the dry mouth. There are dry mouth substitutes on the market -- biotene is one of the better known. There are prescription products to help with the lip and dry mouth also. Look for a good, caring , dentist.