It's self-injurious in the sense that it will look weird to other people, whether they see you do it, or just see the gaps in your lashes and brows.
It's not bad. But it might not be the best idea.
I think it's basically a stim. Perhaps you can substitute a different stim. My daughter used to chew her fingernails compulsively. At some point in her 20s, she started manicuring her nails and applying nail polish. Now she won't chew her fingernails because that nail polish might be toxic if eaten. I'm not sure what stim she replaced it with, but I do think it's possible to select another stim.
I know an older lady who says she knits because if she doesn't knit, she picks at her cuticles until they bleed. I suspect this lady may have some autism traits (for other reasons, e.g. she also has misophonia). But anyway, this is another example of a stim replacement.
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A finger in every pie.