This is a fairly comprehensive review of the variety of approaches you can use to model recurrent events in a time-to-event model. The authors share some code as well. You might need to review some of the references to get a more complete picture of some of these approaches.
Leila DAF Amorim, Jianwen Cai. Modelling recurrent events: a tutorial for analysis in epidemiology. International Journal of Epidemiology, Volume 44, Issue 1, February 2015, Pages 324–333. Available in html format.
An earlier version of this page was published on new.pmean.com.