My "smellbuds" (as I call them) went wrong 10 years ago and I lost my sense of smell, except for really strong smells like bleach. When I fasted for 3 days I got my sense of smell back which made me happy. When I stopped fasting my smellbuds stopped working again.
So in my opinion your sense of smell will go back to how it was before you started your fast.
If it was too heightened before your fast then maybe fasting will regulate it. One of the experts on this forum might know the answer!