Blood after catheterization

Patient: I have a spinal cord injury, and I empty my bladder every 4-5 hours using intermittent catheterization, last month I had large amount of blood came out when I empty my bladder in that way, and the doctor diagonozed me as having multiple false passages, and performed small surgery operation in order to place foley catheter inside my bladder, and it remained for 3 weeks, after I removed it the urine flow normally most of the time when I do my intermittent catheterization but sometimes some bleeding -relatively large amount of blood- occures when doing that (on average one time a day), I wonder if that is ok, should I put the foley catheter again for sometime in order to be fully recovered??please advice, I am alittle afraid of continuos appearing of the problem