Problem analysis:

Based on your situation description, first of all, you have a new lump. The benign tumors with hard lumps include fibromas and sebaceous cysts. If the lump is not red, swollen or painful, It proves that there is no infection, etc. If the tumor is clearly demarcated from its surroundings and has good mobility, it may be more benign.

Opinions and suggestions:

It is recommended that you consider checking the B-ultrasound to roughly clarify the nature of the mass. If it is a fibroma or sebaceous cyst, you can consider surgical treatment.