How to stretch shoes back into shape?

The least drastic thing I can think of is to get a bowl of warm water and apply uniformly to the shoe surface using paper towels. Let the water soak in for a few minutes then use a hair dryer on warm (NOT hot) to dry them back out. You might alternatively try setting them in a sunny window and turning them round every now and then if you don't have time to sit there with the dryer. This should safely shrink the leather somewhat. Repeat as necessary. Do not overdo it. I would apply shoe polish after doing this to remoisturize the leather (do not use oil or lotion - my usual choice for leather care - as those will enable the leather to re-expand).

Hopefully the shoes are smooth leather, not suede (in which case "never mind").

Another thing you can do to "effectively" shrink them (with no danger) is to add an innersole to them. It doesn't take much to make them feel like they have shrunk. This has the added benefit of making them more comfortable.

on the market there are a few leather shrinking creams try them

Seriously some washers have it to where u can wash ur shoes and dry them and u know how doing that makes ur clothes shrink sometimes maybe it will work for your shoes!

put them in the microwave for about a minute or two lol