There are multiple ways to implement microservices. 

REST over HTTP is one of them.

 REST is also used in other applications such as web apps, API design, and MVC applications to serve business data.

On the other hand, in microservices architecture, all the system components are put into individual components, which can be built, deployed, and scaled individually. 

Microservices provide certain principles and best practices that help in building a resilient application. So, we can say that REST is a medium to build Microservices.

https://snipcart.com/blog/microservices-vs-api