Hi and welcome to the board. It depends what fusible you used. Some do soften up, others do not. There are even some on the market that do wash out. Do you know what brand and type you used?
In the future, if you plan to needle turn applique there is no point at all in fusing. If you don't like to pin your applique in place or baste it, you can adhere the applique using elmers washable school glue either the white kind that comes in the bottles or the glue sticks that are usually purple but dry clear. Make sure they are marked Ultra Washable School Glue. Also stay away from the edges with the glue so you can turn it as and also to avoid getting any near where you will be sewing as it can dry hard enough to make it difficult to get the needle through the fibers.
This product will hold your applique in place until you sew it down and then it washes out completely leaving no stiffness at all.
I hope you used a product that will soften up but in my experience all leave in fusibles do change the hand of the fabric. The least noticeable one is mistyfuse.