Hello,
Presence of lumps depends on whether the lump is inside or outside the testes. If it is present on skin then it can be sebaceous cyst or an infected hair follicle (more likely). If it is present inside the sacs, then it can be an epididymal cyst or a benign tumor. This would need further evaluation. Without examination it is difficult confirming, so please get it examined from a urologist. You need to get an ultrasound testis done to confirm the diagnosis. Diagnostic or therapeutic fine needle aspiration cytology(FNAC ) may also be needed to confirm the diagnosis.
Till then apply warm compresses and some topical antibiotics on the lump.
I hope it helps. Take care and regards.