if I am allergic to peanut butter what can I use instead

Speculoos/cookie butter

Oh thank you

Yes to previous good suggestions suggestions....various seed or nut butters, avocado and more.
Also, because pb is mostly legume and fat, also consider - depending on the recipe and harmony with related ingredients - pureed beans or rich thick dairy substitutes (cream cheese or creme fraiche).

Cashew butter is also a good choice! It depends on what you're making of course. For baked goods, I would substitute sunflower seed butter (sometimes called "sunbutter" in recipes) or almond butter. ;o)

And more: walnut butter, hazelnut butter, maybe even Nutella depending on the dish.

Choose wisely based on your own taste preferences and the specific recipe.

Almond butter, sunflower seed butter, avocado, tahini.