Carlow,
Welcome back! Glad to hear you're home and recovering well. Itchiness can mean a few different things.
1. You could possibly have the start of a leak. Meaning the stool got under the wafer around the stoma and is sitting on your skin causing it to itch.
2. You could have a skin sensitivity to the particular brand of flange that you're currently wearing.
3. Yeast Infection
Where exactly is it itching at? If your skin is itchy where the tape is or far from the stoma site, it may be a skin allergy/sensitivity to the product. If it's itchy in the immediate area surrounding the stoma, stool either got under the wafer or the wafer broke down too much and isn't protecting your skin anymore.