It is now time to rejoin the world as a TDD expert. Don't worry if you don't quite feel like an expert yet. You likely have more knowledge than at least one co-worker or peer. To them, you are the expert with knowledge to share. Go forth and share that knowledge. But remember, there is always more to learn.
It may be beneficial to seek out a mentor or mentors. There is likely someone in your community with TDD knowledge who is willing to speak with you. They could be employees of your company or members of the tech community in your city. Seek them out and offer to buy them lunch or meet for coffee. You may find that they’re thrilled to find someone else willing and eager to discuss TDD as a practice.
User groups and meetups are a great place to network. Look for meetings in your area that you could attend. TDD has become a hot topic in recent years and you're likely to find a meeting close by. The programming language may be different from...