Argentina inflation rose back up to 3.8% in December, the government said on Thursday, above forecasts and to its highest level since last April, driven by consumers splurging on festive feasts and holidays in the last month of the year. The result, higher than the median forecast from analysts polled by Reuters of 3.6%, also saw running 12-month inflation clocked at 50.9% in the month. The Consumer Price Index (CPI) had risen 2.5% in November.