Lump on testicle 5 weeks after hernia repair and hydrocele surgery? What is it? Should I be worried?

Check with surgeon. This is likely a residual hematoma or swelling from your hernia repair and should resolve. If not tender or red, you can wait until you see your surgeon as part of your routine post-op check. Otherwise call for an earlier appointment.
Probable swelling. This is likely normal swelling or resolving fibrosis due to post surgical changes but i would definitely being to the attention of your surgeon at your next visit.