I have this thing in between my pinky toe that I thought was a blister but after I popped it, it later looked like an indent in my toe, what is it?

Another option. Deep corns can form between toes which can cause a great deal of pain. It is easy to determine the difference between this and athletes foot in an office. Both treatments are simple and successful. I would have it looked at soon if it doesnt improve with the advice above.
Possible. Soft corn. Be careful with self treating - frequently can end up with further infection. See your podiatrist. (surgery can be done to eliminate that problem if it is what i thought.).
Athletes foot. This whitish slit s a variant of athletes foot. It needs to bedriedout and treated. Whit field ointment can peel away the debris so a topical antifungal cream can penetrate. An o, d fashioned treatment but messy is castellanis paint whic will dry out the debris.
Need a picture. Need to know how long it has been there, how old you are and when you first noticed the blister. Also need to know what kind of fluid was in the blister, was it clear, was it cloudy, if so what was the color.