Great. OK so do 50% water changes, as many as you need, until nitrite test reads visibly under 5ppm. It won't hurt the cycle. Remember to use water conditioner with the water changes.
Since your ammonia eating bacteria are established now you just need to keep them alive until the nitrites drop. Can reduce to 1.5 to 2ppm ammonia dose every second day. Again this won't hurt the cycle and will help in your nitrite readings skyrocketing and potentially stalling the cycle. Keep an eye on your pH. When the nitrites start dropping your pH may start dropping also. Keep it above 7. If your water turns well acidic it will slow or even stall the cycle if the pH drops a lot.