I had tear knee lagiment 1 month now and still on boot cast. Am goin on holiday is it ok to take pain killer?

NSAIDs. NSAIDs ie Ibuprofen for most musculoskeletal injuries are the mainstay of preferred non opiate analgesic treatment. There is also marked reduction in inflammatory factors that improves healing and a quicker recovery time. Before starting an NSAID though please consult your GP for contraindications for taking an NSAID such as Kidney disease or current GI ulceration.