The USDMXN has been pushing higher as US interest rates increased, the dollar increased. The pair moved above its 200 day moving average for the first time since early October on Friday, and moved to a new high going back to early November at 21.6354 during yesterday's trade.
Today with the dollar moving lower, stocks soaring and interest rates back lower, the pressure on the emerging currencies - including the MXN - has abated a bit.
Technically, the USDMXN as retraced back to retests it's 200 day moving average at 21.1599. The prices just dipping below that level to 21.1466 currently. If the price can stay below, the sellers will feel more comfortable that the break above was as short-term phenomena. Move back above and the buyers assume more control.