A woman Shiv Sena worker poured ink over a man in Beed district of Maharashtra after he put up a social media post criticising Chief Minister Uddhav Thackeray.
The man had used the words "nalayak" (unworthy) and "udhvast" (destroyed) in his Facebook post.
Thackeray, who is president of the Shiv Sena, last month joined hands with the Congress and NCP, after his party's alliance with the BJP collapsed over the issue of sharing the chief ministerial post.
He was sworn in as chief minister on November 28.
Last week, some Shiv Sena workers thrashed a Mumbai resident and tonsured his head after he posted a derogatory comment against Thackeray on Facebook.