shoe help.

[starsxinmyxeyes.livejournal.com]

i looked in the memories/archive, but it's all about decorating the outside of shoes, which is not what i'm trying to do. and i don't really know how to google this, so i'm hoping you crafty ladies will be able to help.

i love ballerina flats, but have a problem with most of them. my right foot is considerably smaller than my left foot, and so usually have to wear a hair tie around the shoe to make it stay on my right foot. well, now i have a foot tattoo on my right foot, so i don't want to wear a strap of any sort. i was trying to think of a way to add padding to the inside of the heel; would fabric and superglue work? i don't want it visible from the outside, which is why i'm not leaning towards... sewing, or something like that.
also, i have a pair of shoes, same style, that give me a giant blister across my heel every time i wear them. i figure whatever method i use for the above, i can use for this as well.
basically, i want a way to put padding inside my shoe, across the inside of where my heel is, and i don't want it to look... bad.
any suggestions?