Kegging for the first time question

As stated, cut off the defect seal and start over. You need the barb to be at least the diameter of the hose and it works even better if it's 1/16" larger, i.e. 5/16"(or 3/8") barb to 5/16" hose. Heat it and shrink it and clamp it. This is not the place to be jury-rigging your connection, simple works here. Once you get the process down it'll be automatic. Don't be afraid to put the whole kit-n-kaboodle in a bucket of water to leak test. I use no clamps on my beer lines...3/16" beer line shrunk to a 1/4" barb is leak-proof at beer serving pressures.