Hi I bought the B12 injectable liquid but there's no use by date on it or how long you have to use it once it's opened. Anyone know the answer? TIA x ORDER B12 INJECTIONS ONLINE Free UK Delivery Doctor Led Service 1mg + 5mg Methylcobalamin B12 Dr Ayanna Knight Cosmetic Skin Care, Health & Wellbeing Botox Brighton Vitamin B12 Shots Beverly Hills Rapid Boost for Energy, Mood, & Metabolism Hi I bought the B12 injectable liquid but there's no use by date on it or how long you have to use it once it's opened. Anyone know the answer? TIA x