Here are some flowers with similar pink margins:

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Encore Autumn Debutante

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Minato

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Yayoi No Hikari

I think this is the hybrid: Picotee
(in French that means coloured edge)

See for similarities:

http://www.hirsutum.info/rhododendron-hybrids/indexp.html#picotee

Here is a link that might be useful: Rhododendron Picotee

The flower is so cute. I have searched for the flowers that have color in its edge. There are so many varieties that belongs to this kind. You can search it in Google.

Whatever it is it's beautiful! I can see why it's your favorite.

One thing that is different between the original flower and many other similar picotee flowers is that it is hose-in-hose, meaning that the calyx is transformed into petals, such that it appears to have twice as many petals, one set inside the other and rotated so that all the petals are visible.