Hello and thank you for posting your medical question on E health forum.
From the description provided it seems that the brusing could most probably be due to the recent travel. But they are usually benign and occur as a result of constant friction of the skin.
The bruises will resolve within a week.
If there is any pain , discomfort, you might be benefited by OTC NSAIDs like Ibuprofen, which will reduce the inflammation and also aid in quick healing.
I hope this helps.