Kids Chapter book Fantasy about a girl who shrinks or whose gravity is turned upside down and helps out a kingdom of insects and grubs inside a log

[Dorothy]

- I think the title is something very close to the idea "upside down, inside out" or "topsy-turvy," or at least gave me that impression, but the phrase was tweaked for humor or to subvert expectations.
- This book may be a sequel or has a sequel. I recall that in the book I remember, the kingdom in the log was already familiar to the main character. The cover that I recall features a girl or boy floating up towards a ceiling, looking down from that ceiling. The art seemed very smooth and seamless in texture. The color purple seemed prominent.
- I read this chapter book in 2002-2003. The book seemed newish at the time. It was probably half an inch or so thick. I do not know if its origin was from the USA or the UK, but it was in English.

[Rainbowheart]

Bug Off?

Andrew Lost in the Garden?

Eric in the Land of the Insects?