Prayaschitta

Swami,

I made a grave mistake.
By The Lord's grace I have kept myself
pure physically. I have even managed
to keep a purer mind when talking to women (when I have to).

Today I talked to a married woman
with a very impure mind. She's a neighbor
of my parents I hadn't talked to in years.
She was talking to me for quite some time,
and I let my guard down and started to enjoy it.
I didn't  fantasize about sex, but I did enjoy her company.
She was dressed very scantily (explanation, not excuse).
By the lords grace I didn't commit a physical break.
I was courteous with her - the only possibly flirtatious thing I said was that she hadn't changed a bit, but my mind wasn't pure. The worst of it is that she is married.

I'll be more mindful  from now on, but
did I commit  a break?

What prayaschitta can I do ?