Post-vaccine rash (4mo)

Bub (4mo) had standard shots 4 days ago (DTP, help b, rotovirus) and since yesterday has had a rash spread from nappy line up across stomach, back and behind ears. Baby seems unbothered - no fever and feeding normally.

Saw GP today who was not overly concerned and said post-viral rash is not super common but not unexpected for infants. Bub is also getting her first tooth so GP suspected immune system load may have triggered a stronger response to shots this week as there were no signs of any rash after the same shots at 6w.

I'm not concerned about the vaccines but just wondering if anyone has had this experience? If so, is there anything that helped make it pass quicker?

Can't post a pic but it looks similar to roseola.