It is a fissured tongue ( presence of irregularities) and nothing to worry about. You need extra care for cleaning it . Brush twice daily and clean your tongue too with a brush and not a tongue scraper( types). The only thing is if left unclean, you get halitosis ( bad breath)
Next Steps
Visit the dentist , if there is symptoms like burnnig sensation, pain , bad odour, change in colour or absence of taste sensations.
Hope this helps you.